[General Comment:- My comments have been made in “edit mode” with “Track
Changes” activated. Non edit comments such as this one, appear in brackets []
and are preceded by the words “General comment.” Edits appear as additions or
strikeouts.
The original document contains a considerable amount of highly questionable
and unsupportable language concerning mold exposures that are contrary to
literature, contrary to good industrial hygiene, and contrary to the global scientific
community. The allusion to hazards should be based exclusively on sound,
accepted science.
My revisions have updated the societal reality that many IMGOs may in fact be
authorized as “lawful” according to a State or local jurisdiction; federal standards
notwithstanding. I am called into as many “legal” grow-ops as illegal grow ops
these days.
I believe the document would greatly benefit from some editing to combine like
topics, and improve the overall flow of the discussion such that the discussion
progresses in a logical fashion – as it is, the discussion returns over and again to
assessment/remediation phases .]
AIHA Guideline 13 – 2016
Clandestine Indoor Marijuana Grow
Operations – Recognition,
Assessment and Remediation
Guidance
By
Thomas D. Koch, CIH, MEPM
Carol-Lynn Chambers, MPA, CIH, CSP
Stacy Bucherl
John Martyny, PhD, CIH
John Cotner
Stan Thomas
American Industrial Hygiene Association
Disclaimer
This document is neither a comprehensive treatment of issues concerning clandestine
marijuana grow operations, nor is it a stand-alone resource. Scientific and practical
knowledge in this area is rapidly accumulating and evolving. It is intended to
complement policies and procedures put into practice by other municipalities, counties,
states, or provinces and should be used by the industrial hygienist in conjunction with
existing information.
AIHA and the authors disclaim any liability, loss, or risk resulting directly or indirectly
from the use of the practices and/or theories discussed in this guideline. Moreover, it is
the reader’s responsibility to stay informed of policies adopted specifically in the reader’s
location of practice.
Specific mention of manufacturers, membership organizations, and products in this
guideline does not represent an endorsement by AIHA.
Stock Number: EMRG10-764
ISBN: 978-1-935082-17-0
American Industrial Hygiene Association
2700 Prosperity Avenue, Suite 250
Fairfax, VA 22031
Tel: (703) 849-8888
Fax: (703) 207-3561
E-mail: infonet@aiha.org
http://www.aiha.org
Printed in the United States
Table of Contents
Committee Members
1. Purpose
2. Scope
3. Glossary of Terms
4. What is a Marijuana Grow Operation?
5. Why do Marijuana Grow Operations Present a Public Health Concern?
6. Specific Health and Safety Issues Related to IMGOs?
6.1 Electrical
6.2 Chemical
6.3 Biologic Hazards
6.4 Structural
7. Affected Professionals and Individuals by Stage of Activity
7.1 Initial Response Phase
7.2 Assessment and product Removal Phase
7.3 Evaluation and Remediation Phase
7.4 Re-occupancy Phase
8. Personal Protective Equipment
8.1 Initial Response Phase
8.2 Assessment and Product Removal Phase
8.3 Remediation
9. Remediation Issues
9.1 Preliminary Assessment and Remediation Work Plan
9.2 Mold, Asbestos, and Lead Remediation
9.3 Post-Remediation Assessment
9.4 Building Infrastructure Remediation and Correction
10. References
Committee Members:
Thomas D. Koch, CIH, MEPM
Carol-Lynn Chambers, MPA, CIH, CSP
Stacy Bucherl
John Martyny, PhD, CIH
John Cotner
Stan Thomas
1. Purpose
The purpose of this guidance document is to provide affected individuals and
professionals with information pertaining to clandestine marijuana grow operations
(MGOs) and the hazards they present. Marijuana grow operations are an emerging
problem in our communities with respect to environmental health and safety issues that
can affect a wide range of individuals and organizations. The escalation of Marijuana
Grow Operations (MGOs) in recent years has illuminated the need for addressing the
numerous health and safety hazards associated with these operations. The American
Industrial Hygiene Association (AIHA®) has developed this document in a collaborative
effort with, and in part at the request of, the Office of the Fire Marshal, Province of
Ontario Canada, to address the ever increasing health and safety hazards associated with
clandestine marijuana growing operations.
Health and safety problems are numerous and inherent due to the clandestine nature of
marijuana growing operations, especially when those operations are conducted indoors.
Faulty electrical wiring, the use of grow lamps, the interaction of water and electricity,
the use of chemicals (fertilizers, insecticides, etc.), structural damage can combine to
create dangerous, and sometimes deadly, environments.
2. Scope
IMGOs require an interdisciplinary approach. This document will provide guidance
pertaining to the recognition, assessment, and remediation of IMGOs and is intended for
use by first responders, industrial hygienists, environmental health and safety
professionals, public health officials, and other persons whose responsibilities include
recognition, hazard assessment, law or code enforcement, and remediation of IMGOs.
Readers of this document will become familiar with the following:
 Introduction of the IMGO problem, including potential exposures to first
responders, social service workers, health/code enforcement personnel, property
owners, industrial hygienists, and remediation companies.
 The significance of and inherent problems specifically pertaining to IMGOs.
 Introduction to some of the products and materials used in IMGOs and the general
hazards they present.
 An understanding of the roles different individuals, agencies, and organizations
play in IMGOs, their interaction, and the health and safety exposures they may
encounter.
 Physical and environmental hazards that are typically found in MGOs, including
electrical and wiring hazards, chemical hazards, booby traps, and moisture
problems.



The preliminary assessment process for evaluation of contamination associated
with IMGOs and the framework and guidance to conduct remedial assessments.
The challenges and pitfalls of the subject matter, including the criminal nature of
grow operations, the clandestine aspects of IMGOs, property/ownership issues,
the problems that face health department and code enforcement personnel, and the
inconsistency or complete lack of remediation regulations and requirements.
A list of available resources for professionals who must respond to marijuana
grow operations.
In addition to the information contained in this document, the reader should note the
following:


Although there are similar and parallel issues developing with respect to the
manufacture of other illicit and illegal drugs, such as methamphetamine, ecstasy
and LSD users of this document are advised that the hazards encountered in other
types of clandestine drug production operations can be very different than those
discussed herein. Users are cautioned to conduct additional research should other
forms of drug manufacturing be of concern.
As of the publication date of this document, there are no recognized federal laws
with respect to identification, cleanup, and remediation of IMGOs. Users are
advised to check with state or local health department officials for the most
current requirements pertaining to MGO properties prior to conducting any work
involving assessment and remediation.
3. Glossary of Terms [General Comment – I suggest
moving the glossary of terms to an appendix at the end
of the document
The following terms and definitions apply as they pertain to this guidance document and
clandestine MGOs. The AIHA publication, Glossary of Occupational Hygiene Terms
should be referenced for any terms not defined in this section.
Building – A structure which has the capacity to contain, and is designed for
the shelter of, man, animals, or property, or place adapted for overnight
accommodations of persons or animals, whether or not a person or animal is
actually present. “Building” also includes manufactured and mobile homes.
Cannabinol - psychoactive cannabinoid; a metabolite of tetrahydrocannabinol
(THC).
Cannabinoid - any chemical compound that activates cannabinoid receptors
in the brain. The term includes endocannabinoids (natural human
metabolites) synthetic cannabinoids (including K2, spice and Yukatan Fire),
and ∆9-tetrahydrocannabinol (THC).
Cannabis – A Schedule I Controlled Substance. Mosby’s Medical
Dictionary (5th Ed.) defines cannabis as: “A psychoactive herb derived from
the flowering tops of hemp plants. It has no currently acceptable clinical use
in the United States but has been used in the treatment of glaucoma and as an
anti-emetic in some cancer patients to counter the nausea and vomiting
associated with chemotherapy.”1 The Oxford Concise English Dictionary
(American version), defines cannabis as: “A hemp plant of the genus
Cannabis.”2
Chemical storage area – Any area where chemicals used in MGOs are
stored or have come to be located.
Clandestine drug lab operation – An unlawful operation involving the
processing or disposal of any controlled substance or counterfeit substance, or
its precursors, reagents, waste streams, equipment or drug paraphernalia
regardless of location.
Clandestine drug lab site – Any area including fields, forests, structures ,
motor vehicles, boats, or trailers, affected by conditions and/or chemicals,
associated with a clandestine drug lab operation.
Cleanup – The proper removal and/or decontamination of substances
hazardous to humans and/or the environment.
Contaminant – A chemical residue that may present an immediate or longterm threat to human health and the environment.
Contamination or Contaminated – The presence of a contaminant.
Controlled substance- a drug or other substance, or immediate precursor,
included in schedule I, II, III, IV, or V of part B of Title 21 of the United
States Code (USC) Controlled Substances Act.
Counterfeit substance – any material represented as or intended to be
presented as a controlled substance regardless of the actual chemical
composition.
Data quality objectives – (DQOs) The establishment of a quality assurance –
quality control program that becomes part of a larger hypothesis testing or
decision making process; the results of sampling and analysis may be the
pivotal point upon which decisions are made. The DQOs ensure, through
Fair use copyright exclusion. Mosby’s Medical Dictionary, Fifth Ed. (Anderson, Anderson, Glanze, Eds),
1998
1
2
Fair use copyright exclusion. The Consice Oxford Dictionary, Ninth Ed. (Thompson Ed.), 1995
their prescription, that a statistically sufficient number of samples will be
collected from statistically representative locations in an acceptable manner
by a validated method or method whose uncertainties are sufficiently
characterized. DQOs describe the overall level of uncertainty that the
Consultant is willing to accept in results derived from sampling and analysis.
The uncertainty is used to specify the quality of the measurement data
required, usually in terms of objectives for precision, bias, representativeness,
comparability and completeness (PARCC parameters). The DQOs should be
defined prior to the initiation of any field work.
Decision level- a predetermined concentration, (sometimes called
“compliance level”) used to distinguish between compliant and non-compliant
areas. Decision levels may apply to surface contamination or to airborne
concentrations.
Decontamination – The process of reducing the level of contamination to a
predetermined decision level.
Demolition – The wrecking or taking out of any load-supporting structural
member.
Disposal – The handling, transportation and ultimate disposition of materials
removed from contaminated properties.
Documentation – Preserving a record of an observation through writings,
drawings, photographs, or other appropriate means.
Dronabinol – (Trademark Marinol®. Dranabinol is synthetic, chemically pure
Δ9-THC prescription drug.
Encapsulation – Applying a surface sealant to create a physical barrier
intended to decrease or to eliminate the potential for exposure to residual
contaminants that may exist beneath the physical barrier even after
decontamination.
Hashish – (“hash”) a paste-like material or solid concentration of marijuana
resin, containing upwards of 15% THC.
Hazard – A source of potential harm from past, current, or future exposures.
HEPA filtration – (High Efficiency Particulate Air) A filtering system
capable of trapping and retaining at least 99.97 percent of all monodispersed
particles 0.3 microns in diameter.
Individual sewage disposal system or ISDS – An absorption system of any
size or flow or a system or facility for treating, neutralizing, stabilizing, or
disposing of sewage which is not part of or connected to a sewage treatment
works.
Marijuana – (also "marihuana") means all parts of the plant Cannabis sativa
L., whether growing or not; the seeds thereof; the resin extracted from any
part of such plant; and every compound, manufacture, salt, derivative,
mixture, or preparation of such plant, its seeds or resin. From a regulatory
perspective, “marijuana” does not include the mature stalks of such plant,
fiber produced from such stalks, oil or cake made from the seeds of such
plant, any other compound, manufacture, salt, derivative, mixture, or
preparation of such mature stalks (except the resin extracted therefrom), fiber,
oil, or cake, or the sterilized seed of such plant which is incapable of
germination.
Owner – Any person, firm, or corporation who owns, in whole or in part, the
land and/or structures such as buildings, motor vehicle, trailer, boat, or other
appliance at an MGO.
Photoionization detector (PID) – A device used for the detection of VOCs,
which utilizes ultraviolet light to ionize gas molecules.
Private, residential property – A single family home, apartment, or multiple
family unit or dwelling.
Property – Anything that may be the subject of ownership or possession,
including, but not limited to, land, buildings, structures, vehicles, and personal
belongings.
Removal – The taking out or stripping of material or surfaces to eliminate the
potential for exposure to contaminants on or in the material or surfaces.
Sinsemilla – an highly potent form of marijuana; female hemp plants that are
specially tended and kept seedless by preventing pollination.
Tetrahydrocannabinol - (THC, Δ9-tetrahydrocannabinol), the primary
psychoactive ingredient in marijuana. A multi-ringed structure (see below)
with a linear formula of C21H30O2. IUPAC Name: (6aR,10aR)-6,6,9trimethyl-3-pentyl-6a,7,8, 10a-tetrahydrobenzo[c]chromen-1-ol. Average
molecular weight is 314.46 g/mol; vapor pressure less than 1 mm Hg at
298°K.
Waste disposal area – Any area where chemicals used or generated in the
manufacture of methamphetamine are disposed or have come to be located.
4. Marijuana
In the 1970s, most marijuana was grown in outdoor areas that were hard to find and were
not readily visible to law enforcement. Even today major marijuana operations are still
found outdoors where large numbers of tall plants can be grown, resulting in a higher
biomass of marijuana. However, with new law enforcement techniques using aircraft for
surveillance, these large outdoor operations have become more vulnerable to detection
and, in much of the country, growth is seasonally limited by temperature and light. In
addition, restricting pollination of the female plants in the outdoors is more difficult
thereby limiting the tetrahydrocannabinol (THC) content of the buds. These factors have
lead to a shift towards indoor cultivation. In Florida for example, the number of IMGOs
has increased from 246 sites in 2004 to 1,022 sites in 2008. Other states where IMGOs
are more prevalent are also reporting increases in IMGOs. Additional information can be
found in the Department of Justice, National Drug Intelligence Center, Domestic
Cannabis Cultivation Assessment, 2009.
The use of IMGOs allows for a year-long growing season in which growing conditions
can be controlled, resulting in plants with a higher THC levels per plant. The use of
IMGO’s has resulted in a steadily increasing THC content in marijuana sold in the United
States (see Table 1).
The potency of marijuana, as determined by THC content, grown indoors is almost
always higher than that grown outdoors. Potency of marijuana is dependent on THC
concentration and is usually expressed as percent of THC in the dry bud (or cone) or final
street material. The average THC concentration in marijuana is 1-5%, hashish 5-15%,
and hashish oil 20%. The THC concentration of sinsemilla is up to 17% (with
unconfirmed street rumors of concentrations exceeding 25%).
In order to obtain higher concentrations of THC, a number of environmental factors must
be monitored and kept in balance. The amount of light, the day-night periodicity, the
carbon dioxide level, the humidity level and the temperature must be closely monitored in
order to produce the most potent marijuana. In addition, the plants must be provided with
adequate nutrition and pests must be kept under control. The plants may be raised
hydroponically or in soil, although many of the hazards present are common to both
growing methods.
Table 1: Average percentage of THC in samples of seized marijuana 1988–2000 (Source:
U.S. Dept. of Justice).
Although all of the necessary production factors could be provided in a greenhouse, such
a growth area is very likely to vulnerable to detection by law enforcement officials, and
criminals alike. In order to prevent detection, MGOs are frequently put into a house or a
portion of a house that can be easily concealed.
In order to produce the highest potency marijuana plants, the temperature and humidity
must be closely regulated. Temperatures are typically kept between 21°C and 32°C,
although some sources suggest temperatures as high as 35°C may increase plant growth.
Relative humidity is regulated to range between 50% and 70%, but poor ventilation may
result in levels exceeding 90%. The greater need for secrecy usually results in reduced
ventilation and elevated relative humidity levels.(3)
Elevated relative humidity, coupled with the elevated temperatures and the need for
irrigation, frequently results in fungal problems within the structure. Increased fungal
growth within the residence may result in elevated bioaerosol exposures to residents, of
special concern when children are present. There is also a possibility of structural damage
to the area of the residence where the plants are raised due to water damage and fungal
destruction of building materials. Additionally, offensive fungal odors may persist in a
residence long after the MGO has been vacated.
The use of artificial light is also important in indoor marijuana grow operations.(3) Large
amounts of light that provide in excess of 2,000 lumens per square foot of plant space are
necessary to produce quick growing, potent plants.
The light source must also be regulated so when the growth period is ended and
flowering is desired, the photoperiod can be adjusted to allow the plants to flower. During
the growth phase, the plants are normally provided with light for 16 hours and then
darkness for 8 hours. To enable the plants to flower, the lights must be off for about 12
hours. During this time, the plants must be in total, or nearly total, darkness.
In order to provide these lighting requirements, the lights used are normally high output
metal halide or high pressure sodium lights with controls to turn them off and on. Some
newer grow lights used in green houses may also be utilized. The lights may range from
250 watts to 1,000 watts and multiple light fixtures may be required depending on the
size of the crop. The lights themselves significantly add to the heat loading within the
grow rooms.
INSERT FIGURE 4a and 4b – Artificial lighting in an indoor marijuana grow
operation**
The need for so many lights, coupled with the desire to escape detection, frequently result
in the theft of electricity from power lines. Ad hoc wiring from power lines has resulted
in structural damage to the residences and makeshift electrical lines can result in
electrical fires and structural fires. The lights themselves may result in a fire since any
contact with water may result in an explosion and/or fire.
Chemicals, including fertilizers and pesticides, are also frequently used in IMGOs. When
used in a prudent manner, these chemicals do not cause a great deal of concern. When
used carelessly, their presence may pose a risk to the neighborhood, children associated
with the residence, and anyone occupying the residence after its use as an IMGO.
Several VOCs are emitted by the marijuana itself, which can degrade indoor air quality
due to fugitive emission of the odors. Unfortunately, like most odor issues, the odor of
marijuana is due to a complex and indefinite mixture of various VOCs. To objectively
assess the presence of an objectionable odor due to marijuana, one must recognize that
specific VOCs are associated with marijuana in common groups. One of the common
groups is the terpene group, and in particular, four terpenes are commonly and
consistently associated with the odor of marijuana:
α-Pinene
β-Pinene
Myrcene
Limonene
Although limonene is commonly found in many cleaning products, (and thus in the air) it
is not commonly found in conjunction with the other terpenes. Fortunately, the air can be
readily assessed for these compounds and quantified using an US EPA validated method
known as the TO-17 Method. The analysis for the method is relatively inexpensive.
According to ASHRAE Standard for indoor air quality,3 adequacy of the quality of the
indoor air, can be based on the objective nature and the subjective nature of the air. The
objective nature of the subjective odor can be based on the odor threshold for each of the
primary terpenes. The literature contains various odor thresholds for the terpenes in
question, in general the literature is in agreement with the following odor threshold
values
α-Pinene = 7 parts per billion (ppb)
β-Pinene = 140 ppb
Myrcene =24 ppb
Limonene = 90 ppb
4.1 Toxicology and Use
Recreational doses are variable. A single intake of smoke from a pipe or joint is called an
“hit” and is approximately 200 mg of total smoke. Typically around 30 mg of inhaled
3
ANSI/ASHRAE 62.1-2010 Ventilation for Acceptable Indoor Air Quality, 2010
THC will produce the desired high. By comparison, the legitimate dose rate of Marinol®
(dronabinol) is 0.07 mg/kg/day.
On the street, users may refer to marijuana by many names including pot, reefer, buds,
grass, weed, dope, ganja, herb, boom, gangster, Mary Jane, sinsemilla, shit, joint, hash,
hash oil, blow, blunt, green, kilobricks, Thai sticks; and any number of other names.
Law enforcement personnel dismantling IMGOs can have a positive home-kit urine
analysis and frequently report headaches and “the munchies” during dismantling
operations.
The following is excerpted from the US National Highway Traffic Safety
Administration:4
Absorption is slower following the oral route of administration with lower, more delayed
peak THC levels. Bioavailability is reduced following oral ingestion due to extensive first
pass metabolism. Smoking marijuana results in rapid absorption with peak THC plasma
concentrations occurring prior to the end of smoking. Concentrations vary depending on
the potency of marijuana and the manner in which the drug is smoked, however, peak
plasma concentrations of 100-200 ng/mL are routinely encountered. Plasma THC
concentrations generally fall below 5 ng/mL less than 3 hours after smoking. THC is
highly lipid soluble, and plasma and urinary elimination half-lives are best estimated at 34 days, where the rate-limiting step is the slow redistribution to plasma of THC
sequestered in the tissues. Shorter half-lives are generally reported due to limited
collection intervals and less sensitive analytical methods. Plasma THC concentrations in
occasional users rapidly fall below limits of quantitation within 8 to 12 h. THC is rapidly
and extensively metabolized with very little THC being excreted unchanged from the
body. THC is primarily metabolized to 11-hydroxy-THC which has equipotent
psychoactivity. The 11-hydroxy-THC is then rapidly metabolized to the 11-nor-9-carboxyTHC (THC-COOH) which is not psychoactive. A majority of THC is excreted via the feces
(~65%) with approximately 30% of the THC being eliminated in the urine as conjugated
glucuronic acids and free THC hydroxylated metabolites.
Molecular Interactions / Receptor Chemistry: THC is metabolized via cytochrome P450
2C9, 2C11, and 3A isoenzymes. Potential inhibitors of these isoenzymes could decrease
the rate of THC elimination if administered concurrently, while potential inducers could
increase the rate of elimination.
Blood to Plasma Concentration Ratio: 0.55
Interpretation of Blood Concentrations: It is difficult to establish a relationship between a
person's THC blood or plasma concentration and performance impairing effects.
Concentrations of parent drug and metabolite are very dependent on pattern of use as
well as dose. THC concentrations typically peak during the act of smoking, while peak
11-OH THC concentrations occur approximately 9-23 minutes after the start of smoking.
Concentrations of both analytes decline rapidly and are often < 5 ng/mL at 3 hours.
Significant THC concentrations (7 to 18 ng/mL) are noted following even a single puff or
hit of a marijuana cigarette. Peak plasma THC concentrations ranged from 46-188 ng/mL
in 6 subjects after they smoked 8.8 mg THC over 10 minutes. Chronic users can have
mean plasma levels of THC-COOH of 45 ng/mL, 12 hours after use; corresponding THC
levels are, however, less than 1 ng/mL. Following oral administration, THC
4
Fair use public domain http://www.nhtsa.gov/People/injury/research/job185drugs/cannabis.htm
concentrations peak at 1-3 hours and are lower than after smoking. Dronabinol and THCCOOH are present in equal concentrations in plasma and concentrations peak at
approximately 2-4 hours after dosing.
It is inadvisable to try and predict effects based on blood THC concentrations alone, and
currently impossible to predict specific effects based on THC-COOH concentrations. It is
possible for a person to be affected by marijuana use with concentrations of THC in their
blood below the limit of detection of the method. Mathematical models have been
developed to estimate the time of marijuana exposure within a 95% confidence interval.
Knowing the elapsed time from marijuana exposure can then be used to predict
impairment in concurrent cognitive and psychomotor effects based on data in the
published literature.
Interpretation of Urine Test Results: Detection of total THC metabolites in urine, primarily
THC-COOH-glucuronide, only indicates prior THC exposure. Detection time is well past
the window of intoxication and impairment. Published excretion data from controlled
clinical studies may provide a reference for evaluating urine cannabinoid concentrations;
however, these data are generally reflective of occasional marijuana use rather than
heavy, chronic marijuana exposure. It can take as long as 4 hours for THC-COOH to
appear in the urine at concentrations sufficient to trigger an immunoassay (at 50ng/mL)
following smoking. Positive test results generally indicate use within 1-3 days; however,
the detection window could be significantly longer following heavy, chronic, use.
Following single doses of Marinol®, low levels of dronabinol metabolites have been
detected for more than 5 weeks in urine. Low concentrations of THC have also been
measured in over-the-counter hemp oil products – consumption of these products may
produce positive urine cannabinoid test results.
5. What is a Marijuana Grow Operation?
A new term has entered the American lexicon: “medical marijuana” which is usually
used synonymously with “legal marijuana.” Essentially, all MGOs are illegal, including
“legal” MGOs. Currently, in some states, there is a conflict between Federal Law and
State Law.
The legal arguments hinge on the State’s assertion of the Tenth Amendment to the US
Constitution, which forwards the principle of federalism by providing that powers not
granted to the federal government nor prohibited to the States by the Constitution are
reserved to the States or the people. State legislatures have asserted exemption from
various federal regulations, using the argument of the Tenth Amendment (see United
States v. Darby, 312 U.S. 100, 124, 1941).
The Commerce Clause argument cited in the 2005 decision Gonzales v. Raich5 stated that
growing one's own “legal” marijuana, even if permitted by a State legislature, affects the
interstate market of marijuana. The legal theory was that personal marijuana could enter
interstate commerce, even if the marijuana wasn't intended for that purpose. The
Supreme Court ruled that the cultivation, possession and use of personal “medical”
5
03-1454 Alberto R. Gonzales, Attorney General, et al., Petitioners v. Angel McClary Raich, et al. (United
States Court of Appeals for the Ninth Circuit, 03-15481), Rehearing Denied February 25, 2004, cert.
granted 6/28/2004
marijuana may be prohibited at the federal levels and the federal prohibition may
override any State legislature to the contrary and may regulated by the federal
government under the authority of the Commerce Clause. In the wake of political
maneuverings, confusion over legality has ensued, and as of the printing of this
document, has not be completely resolved.
A generally true statement is that even “legal” MGOs are operated by individuals with
previous criminal histories, convictions, and/or associations with the criminal world. As
such, in general, even “legal” MGOs have an element of criminality associated with
them.
For the purpose of this guidance document, a marijuana grow operation is a property or
location at which marijuana is grown for “legal” or illegal sales on the street. Most of the
information presented herein will pertain primarily to Indoor Marijuana Grow Operations
(IMGOs) as the indoor or confined nature of these types of operations present health and
safety hazards that are different and often more numerous than if the grow operation
occurs outdoors. In many instances, however, some of the same hazards described in this
document will be encountered in both indoor and outdoor marijuana grow operations.
MGOs can be found in urban, residential, and rural communities; on large acreages or
farmland, in public, private, and commercial properties; on public lands, including
national parks and forests; and in abandoned or unoccupied structures, with or without
the property owners’ knowledge. MGOs can be maintained and/or guarded by the
perpetrators or can be nearly autonomous operations requiring limited daily oversight.
**INSERT FIGURE 1 (Typical indoor marijuana grow operation)**
Figure 1 – Typical indoor marijuana grow operation
MGOs, while they can present significant health and safety problems, are relatively easy
to initiate and can produce crops every three months. In a practical sense, MGOs are, in
principle no different than any other large-scale agricultural production operation and
share many of the same hazards. The presence of chemicals, fertilizers, pesticides,
fungicides, etc. used in growing plants present hazards to those exposed, especially if not
used in accordance with manufacturer’s recommendations (which in most cases they are
not). In the case of an IMGO, some of the hazards are similar to those encountered in
commercial greenhouses, including the prevalence and interaction of water and
electricity, suspended electrical wiring, suspended electrical grow lamps, and the control
of moisture and humidity to prevent mold growth. There are some common or typical
warning signs that signal that a property may be used as an MGO or IMGO.
However, IMGOs differ from other legitimate commercial indoor agribusinesses in that
the operations are usually clandestine and conducted in structures not suited for the
operation– even otherwise “legal” grow operations are typically conducted in a
clandestine manner in a structure not suited for the operation.
The following warning signs were generated by the Province of Alberta Canada Solicitor
General and Public Security in 2008 in an effort to inform property owners or other
individuals of some characteristics of IMGOs(1):

Strong, pungent, ‘skunk-like’ odors emanating from the building.

Windows boarded or covered up and always closed. Aluminum foil is often used
as a window covering.

Residents are present at irregular times. They may be home only a few hours then
leave. There may be unusual visitor behavior.

Sounds of electric humming or fans coming from the home. These sounds could be
given off by lights and electrical transformers used to provide heat and false
sunlight.

Localized power surges or decreases in power.

Signs of digging or disturbance around the outside of the hydro box (electric
meter).

Little outdoor maintenance (i.e., snow not shoveled, uncut grass).

Layer of condensation on the windows.

Entry to the house is often made through an attached garage or side/back entrance
to conceal activities.

Unusual electrical hook-ups to the house or outbuildings.

Persons hauling or constructing a watering system in a building.

Equipment such as large fans, lights, plastic plant containers used in the growing
operations being carried into the home.

Persons hauling suspicious types of material or garbage away from their buildings
and property (i.e., plastic sheeting, fertilizer bags or containers, plant stocks,
plastic piping materials, plastic pots, carbon dioxide tanks, fuel tanks, etc.).

Abnormally warm buildings. In winter, snow may melt off the roofs of buildings
used to house the grow operation.
6. Why Do Indoor Marijuana Grow Operations Present a
Public Health Concern?
An IMGO can have the same characteristics as any greenhouse operation with the
primary public health concerns of chemicals, fertilizers, pesticides, light, and humidity
controlled. And in this regard, the potential hazards could be mitigated in the same
manner as they are in any commercial operation, using good industrial hygiene practices.
Since a residential structure is not designed to function as a greenhouse, contamination is
more difficult to control, moisture can cause more damage, the risk of fire is significantly
increased, and children present in the residence may be at serious risk.
In the case of IMGOs, a great effort is extended to prevent detection by law enforcement,
landlords, parents, and criminals. Additional hazards due to the nature of marijuana as
opposed to other greenhouse operations include the potential for violent criminals.
The clandestine nature of “legal” and illegal operations which may result in steps being
taken that cause significant exposures or risk of exposures to neighbors and to the
community at large.
Often the operator of an IMGO extracts THC using butane gas or other highly volatile,
highly flammable gas. These operations are extremely dangerous, and if performed in
multi housing units, endanger the safety of all occupants. Often the operation goes awry
and explosions and fires are not uncommon.
Another environmental factor important in raising high potency plants is an elevated
carbon dioxide level.(4,5) Carbon dioxide levels in normal outdoor air range from 300 ppm
to 400 ppm. For maximum potency, the grow operators attempt to maintain carbon
dioxide levels in exceeds of 700 ppm, with 2,000 ppm being the highest desirable level.
Most growers attempt to keep carbon dioxide levels between 700 ppm and 1,500 ppm.
**INSERT FIGURE 2 Supplying carbon dioxide directly to plants via modified
exhaust ventilation from a hot water heater. (Courtesy of the Westside Interagency
Narcotics Team, Portland, OR)**
While these levels are not of public health concern, they do cause ancillary problems.
First, in order to keep carbon dioxide levels high, ventilation rates normally need to be
reduced so that the excess carbon dioxide is not evacuated from the area.
Secondly, if the carbon dioxide is generated by the use of fossil fuel combustion, carbon
monoxide, oxides of nitrogen, and ultrafine particles (UFPs) may be released. Very often
the operators will burn propane in the growing rooms to increase carbon dioxide
concentrations. Propane burners, although cleaner than fossil fuel combustion produces
significant quantities of water vapor, UFPs and, occasionally, carbon monoxide.
Both of these combustion by-products can be very dangerous and cause adverse health
effects to exposed individuals. Growers often knock holes through walls, ceilings and
floors to run flex duct through them to promote the circulation of carbon dioxide.
Typically, no thought is given to structural integrity.
**INSERT FIGURE 3 – Modification of exhaust ventilation to redirect carbon
dioxide
[General Comments – This next section doesn’t really have anything to do with the
public hazard presented by IMGOs. Rather this could neatly fit into a new section
containing general information on marijuana. Such a section does not currently
exist in the document. I recommend that a general discussion section be created into
which we could also include a discussion on toxicology and some of the regulatory
issues various states are facing. I have therefore, moved the appropriate portions of
the discussion into a newly created Section 4]
In addition to the environmental concerns just described, there may also be significant
community concerns due to the criminality of the individuals involved. Virtually all
IMGOs, including “legal grows” are associated with organized crime and/or the general
criminal world, and may be equipped with booby traps and firearms. Booby traps are a
major concern for first responders as they may encounter these unknowingly and
experience injury. Individuals working in these operations may be paranoid and take
unwarranted steps to protect their crop. Frequently, families with children are used to
grow the marijuana since a family in a residential area may be less conspicuous than a
group of individuals without children.
Exposure to the potential hazards previously described may result in a community public
health concern. Although the greatest impact is borne by the individuals residing in the
residence, others may also be exposed. IMGOs located in multi-family buildings may
allow the chemicals used and/or produced into the ventilation system for circulation to
other attached living units. Fires and explosions may also cause damage to the IMGO and
to surrounding properties. Lastly, these operations may go undetected for a period of time
and may be sold to an unsuspecting buyer.
7. Specific Health and Safety Issues Related to IMGOs
Many of the hazards associated with MGOs can be found in other environments or
workplaces, such as farms, greenhouses, and seemingly safe residential environments.
7.1 Electrical
Electricity is critical to the function of an IMGO. Growers are notorious for overloading
circuits and using unapproved wiring and electrical equipment, greatly increasing the risk
of fire.
**INSERT FIGURE 5 – Modified electrical distribution and overloaded circuits**
Common electrical devices include: high wattage lights, fans, automatic timers, pumps,
generators, and ballasts. Large operations consume 3 to 10 times the amount of electricity
used by a normal household. This consumption can be monitored by utility providers
used by law enforcement to identify MGOs.
There are two primary ways to siphon electricity off the grid: tamper with the meter or
construct an illegal connection to bypass the meter. There are several methods of
tampering with electrical meters, most of which depend on the type of meter in use. Older
models, for instance, can be adversely affected by high power magnets.
A common and easy tampering method involves disconnecting a meter's neutral
connector. This is hazardous because shorts can then pass through people or equipment
rather than a metallic ground to the generator.
Signs of tampering include:






Cut wires on the plastic closure tags on the meter cover
Holes or metal in the plastic meter cover
A meter cover that is pried up from the meter box
Scorch marks on the meter cover
Extra wiring or missing wiring
Meter is upside down
Some growers bypass the electric meter to conceal their power use. They do this by
tapping into the electrical grid before it reaches the meter. These taps can cause power
surges and electrical system failure due to high loads, which can lead to power outages
and damage to the electrical grid, including the premature failure of distribution
transformers.
**INSERT FIGURE 6 – Electricity is bypassed around the home’s meter box
(Courtesy of the Westside Interagency Narcotics Team, Portland, OR)**
BC Hydro (Canada) estimates that they lost $12 million in grow-related electricity thefts
for fiscal year 2003. Others estimate that the average bypass steals electricity worth
between $1,100 and $1,600 per month. In the United States it is estimated that theft of
power due to IMGO may be as much as 1–2% of all sales.
Electrical poles in a typical United States residential neighborhood carry 7,200 volt lines.
The transformer on the pole steps the voltage down to 240, which is normal household
service. There are usually 100 to 200 amps of power running through an average
residential meter. The danger from electrocution is substantial when tampering with this
kind of power.
The process of creating a bypass to steal electricity involves digging and exposing high
voltage lines or climbing to access high voltage lines. Ballasts are used to convert the
10,000-watt wire into the 60,000 watts often required to run the grow lights. The wire
outside of the home is exposed and not grounded.
**INSERT FIGURE 7 – Illustration of bypassing electric meter and tapping
directly to power grid**
This can result in the possibility of the surrounding area being electrically charged and
dangerous to passersby and emergency responders. Even after power is cut, the interior of
the dwelling can still pose a serious risk because the ballast and capacitor used to boost
the wattage can still retain an electrical charge. In addition, crudely-made bypasses can
electrify the conduit, which, if connected to a home’s ground rod, could then electrify the
surrounding area.
Signs of tampering include:






Electrical splices
Wires into the drip loop before the weather head on the pole
Digging around the electrical meter
Wires on the ground
Open holes in the ground
Bore holes through concrete walls or floors
7.2 Chemical
Several chemicals are used in the production of marijuana. The primary concerns are
pesticides, fertilizers, waste products, THC concentrating solvents, and combustion
products. Not all of these chemical classes may be present at all IMGOs and the actual
substances used may vary based on the grower and geographical area. It is important that
personnel entering IMGOs are protected against all of these possibilities until the
chemical hazards have been assessed.
7.2.1 Fertilizers
Under most conditions, the fertilizers utilized in MGOs are similar to normal household
fertilizers used for other indoor plants.(6) The most common fertilizers are chemical
fertilizers with a nitrogen/phosphorous/potassium percentage of 15/15/15 or 20/20/20.
During the flowering stage the phosphorous portion of the fertilizer is often boosted.
Most fertilizers also contain some trace minerals such as calcium for pH control and
copper, zinc, and iron. Manure is used in some cases, but this is uncommon.
Fertilizers may improve fungal growth by providing nutrients in areas where they are
used and spilled. - . [General Comment -Citation?]In general, the use of fertilizer in an
IMGO is not likely to result in significant health hazards to the growers or to entry
personnel.
7.2.2 Pesticides
The use of pesticides in IMGOs is extremely variable. Pesticide use varies based on
geographic location, indoor versus outdoor grows, the presence of certain pests and the
availability of pesticide. Operations utilizing hydroponic growing techniques or that are
using only inside plants may not have a high risk of plant pests. These operations may not
need to use any pesticides. IMGOs that start growing some of their plants outdoors are
more likely to have plant pests and may begin using pesticides. A study conducted in
British Columbia found pesticides in only 12% of the MGOs tested (5/40).(7) Anecdotal
reports from others in Canada have suggested that a wide variety of pesticides have been
used, some being pesticides that had been banned in the U.S.
In the British Columbia study, organochlorine pesticides (chlordane, dicofol),
organophosphate pesticides (malathion, chlorpyrifos) and a number of pyrethroid and
synthetic pyrethroid pesticides were identified. These pesticides may cause illness in
exposed individuals if the exposure is high enough or if the pesticides are misused. Some
organochlorine pesticides may be carcinogenic. The organochlorine pesticides, although
not extremely toxic, are persistent and can remain in the environment for an extended
period of time. Most of these pesticides have been banned in the U.S. due to
environmental concerns. It is important to note that the rules pertaining to the use,
handling, and disposal of pesticides vary internationally and from state to state.
Organophosphate pesticides are toxic and can be ingested, inhaled, or absorbed through
the skin. These pesticides are cholinesterase inhibitors with exposure resulting in a
phosphorylation of the acetyl cholinesterase present at the nerve endings. Exposure may
result in a number of neurological symptoms such as headache, muscle twitching, nausea,
respiratory depression, and miosis. In cases of high exposure death may occur due to
pulmonary edema and respiratory failure. The symptoms can usually be mitigated by
using atropine and pralidoxime (2-PAM) and by decontaminating the exposed
individual.(8)
The pyrethroid and synthetic pyrethroid pesticides are the most common indoor pesticide
encountered and are frequently considered to be non-toxic. Pyrethrum is manufactured by
extracting the oleoresin from dried chrysanthemum plants and typically causes allergic
dermal and respiratory reactions. Neurotoxicity has also been associated with high
exposures to these compounds. In general, exposure to these pesticides is not likely to be
a concern unless the exposure is high.(8)
Other pesticides such as carbamates, bacterial pesticides, fungicides and herbicides may
be found at IMGOs. Any pesticides observed at the site should be handled carefully until
characterization of the pesticide can be conducted. Organochlorine pesticide
contamination is difficult to mitigate and can persist in the environment.
7.2.3 Combustion Products
As described earlier, the potency of the marijuana produced can be enhanced by the
presence of high levels of carbon dioxide. The optimal level of carbon dioxide in IMGOs
can range from 700 ppm to 1,500 ppm. These levels of carbon dioxide are higher than
those commonly found outdoors, typically 300ppm to 400ppm, and do not pose a health
hazard to exposed individuals.(5)
The hazard with carbon dioxide levels is associated with how the carbon dioxide is
generated in the operation. In some IMGOs, the carbon dioxide is obtained using
compressed gas cylinders of carbon dioxide. In other cases, the carbon dioxide is
obtained by venting fossil fuel combustion into the grow room area. Very often,
specially designed propane gas burners are used to generate the CO2 (see photograph
below).
Depending upon the burning efficiency of the combustion unit, carbon monoxide,
ultrafine particles, and/or oxides of nitrogen are produced during this process. These
combustion byproducts are known to present health hazards.
Carbon monoxide is formed by incomplete combustion of fossil fuels. It combines with
hemoglobin in the blood with a much higher binding force than oxygen (210 to 250 times
greater affinity) to form carboxyhemoglobin. The normal half-life of carboxyhemoglobin
in the blood is 2 to 6.5 hours when breathing air. If supplemental oxygen is provided, the
half-life is reduced to 40 minutes and with hyperbaric oxygen it can be reduced to 20
minutes. Hyperbaric oxygen is frequently used to prevent or reduce the symptoms of
carbon monoxide poisoning. Exposure to elevated levels of carbon monoxide may cause
headache, dizziness, nausea, confusion, nerve damage, coma, and death. Symptoms may
be recognized at carboxyhemoglobin levels as low as 1%, and levels in excess of 50%
may result in death.(8)
Incomplete combustion will also produce oxides of nitrogen. The oxides of nitrogen are
produced by the reaction of an ignition source and natural nitrogen in the air. Symptoms
from exposures to oxides of nitrogen are known irritants and may cause pulmonary
irritation, especially in susceptible individuals such as asthmatics. Levels of nitrogen
dioxide as low as 0.1 ppm may result in increased lung irritation, and levels exceeding 3
ppm may result in a drop in lung function for exposed individuals.(8)
Ultrafine particles
As propane or natural gas is burned in CO2 generators, UFPs are generated. The
particles are primarily composed of reduced carbon nanoparticles.
As the size of a respirable particles decreases, the inherent toxicity of the constituents of
the particulate becomes less important. Otherwise “non-toxic” materials appear to
exhibit toxic properties when the inhaled particles are sufficiently small.6
For example, titanium dioxide particles, at a diameter of 5 µm and larger, are virtually
non-toxic to humans and many other animals (excluding pneumoconiosis issues).
However, titanium dioxide particles with an aerodynamic diameter of 20 nm cause a
severe inflammatory response in the lungs and produce lung damage.7 A similar
response is seen with particles as biologically inert as Teflon8 and carbon black.9
UFPs, such as those associated with the carbon particles10 are implicated in a variety of
respiratory dysfunctions. There is considerable evidence that UFPs may be a significant
factor in the increasing incidents of asthma. 11
Although not all research supports the adverse effects of “non-toxic” UFPs adversely
effecting humans in an equal manner,12 even those studies that question whether all UFPs
are equally hazardous recognize, in principle, the potentially grave health hazards
associated with UFPs.
Oberdorster, G; Gelein, R.M. et al “Association of Particulate Air Pollution and Acute morbidity:
Involvement of Ultrafine Particles?” Inhalation Toxicology 7:111-124. (1995)
6
Stone, V.; Donaldson, K. Small particles – Big problem, The Aerosol Society Newsletter No. 33, Sept,
1998
7
8
Gunter Oberdorster, Robert M. Gelein, Juraj Ferin, Bernard Weiss Association of Particulate Air
Pollution and Acute Morbidity: Involvement of Ultrafine Particles? Inhalation Toxicology 7:111-124.
(1995)
Stone, Vicki; Donaldson, Ken, 1998, "Small particles – Big problem" The Aerosol Society Newsletter No.
33, September 1998
9
10
Klepeis, NE, Nazaroff WW Emissions Characterizing Size-Specific ETS Particle Emissions,
Proceedings: Indoor Air 2002, Monterey, California
Surveillance for asthma- United States 1960-1995” Morbidity and Mortality Weekly Report, April 24,
1198; 47 (SS-1)
11
Green LC; Crouch EAC; Ames MR; Lash TL What’s Wrong with the National Ambient Air Quality
Standard (NAAQS) for Fine Particulate Matter (PM2.5)? Regulatory Toxicology and Pharmacology 35,
327–337 (2002)
12
One such study13 quoted:
Before discussing some toxicologic and epidemiologic issues, we point out that positive
associations from these studies, if causal, suggest that ambient PM is remarkably deadly.
The health hazards associated with UFPs are not well understood, but several cases of
illness, and even documented cases of death14 from exposures to elevated UFPs, are
found in scientific and medical literature.
It is difficult to establish, with confidence, a dose-response relationship with UFPs unless
the actual particulate size distribution and the surface chemistry of the UFPs is known.
There are studies that have included measured UFP concentrations in occupational
settings and have found significant health hazards at UFP concentrations of 34,000
particles per cubic centimeter of air.15 In this case, the UFPs were from asphalt fume
generation.
Since the information concerning adverse health effects of UFPs is still emerging, and
insufficient knowledge exists at this time to establish a general exposure limit, the AIHA
Committee cannot, with confidence, provide specific guidance on “safe” vs. “hazardous”
concentrations of UFPs. However, some authors16 have reported that at sufficiently small
particles, the actual composition is not important, and when for example, they instilled
UFPs of biologically inert Teflon into rats at concentrations as low as 40,000 particles per
cc of air, the concentrations were sufficiently elevated to result in pulmonary
hemorrhaging in the rats. This value is remarkably similar to the 34,000 particles per cc
reported above (ibid, Elihn 2008).
Currently, there are no generally accepted occupational exposure standards for UFPs.
Although OSHA does regulate respirable particles, the standard is based on a mass per
unit volume basis and, therefore, does not take into account particle number or surface
area issues which are known to play an important role in the adverse health effects of
UFPs. According to OSHA, respirable particles cannot exceed 5,000 micrograms per
cubic meter of air (µg/m3) based on a time weighted average. But even at 200,000
particles per cubic meter, for unit density particles, the mass of an airborne insult would
only be approximately 0.004 µg/m3.17
13
Ibid
14
Song Y, Li X, and Du X Exposure to nanoparticles is related to pleural effusion, pulmonary fibrosis and
granuloma, European Respiratory Journal; 34: 559–567, 2009
15
Elihn K, Ulvestad B, Hetland S, et al Exposure to Ultrafine Particles in Asphalt Work, Journal of
Occupational and Environmental Hygiene, 5: 12, 771 — 779, 1/12/08
16
Oberdorster G, Finkelstein JN, Johnston C, Gelein R, Cox C, Baggs R, Elder AC. Acute pulmonary
effects of ultrafine particles in rats and mice. Res Rep Health Eff Inst. 2000 Aug;(96):5-74; disc. 75-86.
17
Qualitatively calculated from the density derived from carbon/iron oxide composition of common copier
toner, and an estimated nominal particle size.
NIOSH suggested 2.4 mg/m3 for agglomerated fine spherical TiO2, but 0.3 mg/m3 for
TiO2 UFPs. NIOSH also has proposed a “Recommended Exposure Level” of 7 µg/m3
for carbon nanotubes and carbon nanofibrils; Nanocyl (a leading global manufacturer of
specialty and industrial CNTs) proposed 2.5 µg/m3 for certain CNTs; Bayer Corporation
suggested 50 and AIST Japan has suggested 250. Therefore, there is still considerable
debate about the most appropriate exposure metric and exposure value.
Using typical CO2 generators in a volume approximating a single story residence of
1,500 square feet, it has been estimated that UFP concentrations may be as high as 82,000
particles per cubic centimeter of air (82,000,000,000/m3). At this concentration, an
infant in the home would be inhaling approximately 3 million particles per breath.18
7.2.4 THC Concentrating Solvents
In the past, the THC content of marijuana typically ranged from 1–5%. The use of
improved growing techniques made possible in an indoor growing environment has
increased THC levels above 10%. The levels are still rising. Sinsemilla, derived from the
unpollinated female cannabis plant, commonly has THC levels as high as 17%. Hashish
has similar THC levels that range from 5–15%, and hashish oil or hash honey oil has
THC levels averaging 20%.(2)
Hashish is produced by removing the trichomes (small hair-like projections on the buds)
using any one of a number of mechanical means.(9) Once the trichomes are removed, they
can be pressed to make hashish or they can be further purified to produce higher levels of
THC. This technique to produce hash oil requires the use of a solvent. One methodology
utilizes a PVC pipe that is filled with pulverized plant material and capped. Butane is
allowed to enter the top of the pipe through a hole. It moves through the plant product
and into a receiving vessel. The butane is allowed to evaporate, leaving behind the hash
oil. Alcohol may then be used to bring the oil into solution and move it to another
container.
Other solvents such as isopropyl alcohol can be used to extract the hash oil. Plant
material is combined with the solvent in a container and coffee filters are used to separate
the plant material from the liquid. The resultant solution is heated and the alcohol is
evaporated to produce hash oil.
18
Tidal volume is similar for adults and children on a ml/kg basis (Rusy L, Usaleva E Paediatric
Anaesthesia Review; Practical Procedures, Issue 8, 1998), therefore, the value assumes a tidal volume of 42
cm3 for a 6 kg infant of 5 months age.
Butane and isopropyl alcohol are both extremely flammable with very high vapor
pressures.(10) Heating of these materials is extremely dangerous and using them near an
open flame may result in a fire and/or explosion. The ensuing conflagration can pose a
serious danger to surrounding structures and the community as a whole.
7.3 Biologic Hazards
Elevated temperature and humidity commonly found in IMGOs can create an ideal
atmosphere for fungal growth. The Canada Mortgage and Housing Corporation (CMHC)
references a November 2004 Royal Canadian Mounted Police Marijuana GrowOperation Conference wherein the RCMP engaged eight newly certified individuals who
had completed CMHC’s “Residential Indoor Air Quality (IAQ) Investigator Training
Program.” The newly qualified inspectors evaluated 12 residences used as IMGOs.
Although the newly certified inspectors did not conduct any quantitative assessments for
molds, based on their visual inspections, they found that 7 of the residences had
extensive visible mold contamination; 2 of the homes had moderate mold contamination,
and one house had no signs of moisture damage and no signs of mold. The CMHC did
not identify the conditions of the remaining two houses.(11) All of the residences were
associated with a musty smell. [General Comment – CMHC did not conclude that the
musty odor was fungal in nature and the “musty odor” could have been due to soil borne
Actinomycetes, cyanobacteria, geosmins, or 2-methylisoborneol associated with wet
materials and soils, or even a background odor due to the fact that all the residences in
question (except one) had been unoccupied for various periods of time. ] [General
Comment – This is not what was reported by McLaren and Swift in the cited reference.
In the actual paper, McLaren merely commented that another author, (McPartland, 2002)
referenced a study from yet another (unidentified) author who apparently found the
presence of Aspergillus in 13/14 plants that were tested; no information was given on the
“testing” or the levels or the significance of the levels or the validity of the tests. Thus
the same statement regarding the presence of Aspergillus could equally apply to
commercial corn, beans, or household geraniums. McLaren never made any statement
about “excess amounts.” I don’t have McPartland’s book (Cannabis and Cannabinoids:
Pharmacology, Toxicology, and Therapeutic Potential. New York: Haworth Press; 2002,
p. 337–43) so I don’t know what McPartland actually said or found, however the
referenced article has been misquoted.]
Mold species commonly identified in indoor marijuana grows include Acremonium,
Penicillium, Rhizopus, Fusarium and Aspergillus; which are normal fungi found in
virtually all occupied houses to some extent. In some cases, these fungal species may be
found at elevated levels within the IMGOs [General Comment – unless there is a
reference, this statement is speculative and should be struck or the term “elevated levels”
put into context with other agribusiness operations such as green houses workers or
nursery workers]. [General comment – unless there is a literature citation to support this
statement, it is speculative, and it is contradicted by published literature and should be
struck ]Molds release spores, , [General Comment- I am not familiar with any moulds
that release endotoxins, and I’m not familiar with any fungal endotoxins at all – is there a
reference for this statement?] and other fungal components that may result in allergic
reactions in susceptible individuals. Those susceptible individuals (such as atopic
individuals) exposed to some types of mold, and their spores, , [General Comment Even in extremely mouldy conditions (see Brasel & Martin) authors have reported
mycotoxin values only as high as 0.0000001 ppm. Under even extreme mouldy
conditions, the daily dose of mycotoxins identified was 8.9E-10 times below the LC50
reported by Wannemacher and 5.9E-6 times below the LOAEL reported the by the
European Commission Health & Consumer Protection Directorate-General. To my
knowledge, mycotoxin exposures have never been demonstrated to be an issue in a
IMGO. ] may develop a wide range of symptoms such as allergic rhinitis, skin rash,
itchy eyes, headache[General comments – citation?], nausea [General Comments –
citation?]. In some instances where the exposure is high and/or prolonged, more serious
illnesses, such as [General Comment – the 2004 German Guide: The Prevention,
Investigation, Evaluation and Rehabilitation of Mould Growth Indoors (Indoor Air
Hygiene Commission of the Federal German Environmental Agency, 2002) states: “Very
rare and almost exclusively occurring in the workplace is extrinsic allergic alveolitis
(hypersensitivity pneumonitis) which is generally produced by repeated exposure to very
high concentrations of spores (1E6-1E8/m3 ); which cannot be expected to occur
(residential) indoors.” Based on state of knowledge, the idea that a IMGO can cause HP,
is speculative. ] [General Comment – the inclusion of asthma in this context is contrary to
the findings of the 2004 US Institute of Medicine (IOM), National Academy of Sciences
findings published in Damp Indoor Spaces and Health and contrary to the findings of the
2009 World Health Organization Guidelines For Indoor Air Quality Dampness And
Mould. If there is some kind of citation that can be included to support this statement it
should found – otherwise the language should reflect known science ], reactive airways
disease [General comment- citation or speculation?], and other allergic illness may occur.
Individuals who suffer from weakened immune systems due to cancer, AIDS, leukemia,
an organ transplant, chemotherapy, take medications that lower the number of normal
white blood cells or otherwise weaken the immune system may develop a very rare
condition known as aspergillosis.. The inhalation of significant amounts of fungalcontaminated dust can result in an illness called Organic Dust Toxic Syndrome (ODTS)
which is associated with fever, flu-like symptoms, and respiratory effects.
**INSERT FIGURE 8a and 8b – Mold growing in an IMGO**
A number of law enforcement agencies throughout the U.S. and Canada have conducted
indoor air quality studies at indoor marijuana grow houses. The results of these studies
indicate an increase of viable and non-viable mold within the structures. [General
Comments – citation?] [General Comments – citations?]Locations, such as living rooms
and kitchens, are often used by law enforcement officers to conduct administrative duties
such as bagging evidence, filling out paperwork, and completing legal forms.
[General comments – citation? Study?] [General comment – this is the normal expected
range of variation that we could expect to see in simultaneous side-by-side samples
collected from the same room at the same time; without a statement of standard error or
precision or standard deviation, the reported “increase” can be due exclusively to
sampling error alone. We have seen variation between collocated side-by-side samples
as high as 2,500% for two spore traps collected at the exact same time, in the exact same
location separated by only 90 cm.
[General Comment – this statement lack PARCC validity and should be struck or the
PARCC parameters should be given. Normal, dry houses with no known mould
problems and no marijuana growths can easily exhibit an indoor-outdoor comparison
100:1 based on single spore counts. Unless there are PARCC parameters to provide
context or confidence to these numbers, this is just playing the “numbers game” without
meaning. ] [General comments – are there data to back this statement?[General
Comment – what study? Citation?][General Comments – the data presented could be
equally applicable to any home, and or any structure. Sweeping a dirty floor or even
running a vacuum in a dirty house could easily result in these kinds of mold counts.
Consider for a moment that lumber mill exposures to spores run 1,000,000 spores/m3 to
100,000,000 spores/m3 [Gotts, 2010]; normal daily potting shed exposures to just
Stachybotrys alone at are reported in the literature at 7,500 spores per m3 9 Dill and
Trautmann, 1997); and normal February outdoor exposures in New Orleans range from
11,000 to 81,000 (National Resources Defense Council) unless the reported numbers can
be put into some kind of defensible context, they should be eliminated.]
To date, studies have not shown a correlation between the number of marijuana plants
and the prevalence of viable or non-viable mold spores. There are concerns within the
law enforcement community pertaining to the health effects associated with the
investigation of IMGOs. Concerns include rash, asthma exacerbation, allergic rhinitis,
and other lung problems. These unsupported but perceived health threats have resulted in
a number of law enforcement agencies requiring personal protection equipment to enter
IMGO's. However, the actual need, based on standard industrial hygiene decision
criteria, for some of the requirements has not been confirmed.
This data [General comments What data?], in combination with earlier studies[ General
comments – What earlier studies?], reflects definite trends and principles that support
sensible operational response to indoor marijuana cultivation operations. These include,
but are not limited to, the following:




Expect most indoor marijuana cultivation operations to have elevated
concentrations of airborne mold spores; however, there are no indications that
those exposures are any greater than would be expected in any other legitimate
green house or nursery ].
Neither plant number nor plant size is the primary predictor of the concentration
of airborne mold spores.
A room other than the primary marijuana grow room can have the greatest mold
concentration in the grow-house.
Increasing the officer’s distance from the primary marijuana grow room does not
necessarily predict a decreasing exposure to airborne mold spores.


A visually “clean” house doesn’t guarantee freedom from high airborne
concentrations of mold spores.
Currently there is no supportable science to indicate that exposures to molds in
IMGOs poses a significant threat to the health of responding personnel.
7.4 Structural
Growers are more concerned with maximizing profits and accelerating grow cycles than
preventing structural damage. The illegal nature of an IMGO operation can result in
modification of building structures and foundations to accommodate secret entries and
passageways. Growers also cut holes in floors and load bearing walls to promote
circulation and create pathways to run electrical wiring and duct work. These
modifications can pose significant hazards to both occupants and first responders. The
International Association of Fire Fighters (IAFF) considers structural alterations one of
the primary hazards associated with IMGOs.(13)
**INSERT FIGURE 11 – Modification of foundation to facilitate electrical
distribution**
The prevalence of water and moisture in IMGOs, especially when present over long
periods of time, can have damaging effects to building materials and components. The
integrity of concrete foundations, wood and metal framing, drywall, and plaster can be
severely compromised if exposed to excess moisture or humidity over time.
Moisture damage can also affect the integrity of wood framing, attic spaces, and plaster
and drywall systems that comprise internal walls and ceilings. Excess moisture can create
the potential for sagging and complete collapse of drywall or plaster ceilings. Wood
floors can become damaged to the point that they can no longer support the weight of a
human, creating fall hazards. Ceilings may need to be stabilized and shored up in order to
complete a safe and thorough evaluation of the property. Those persons involved in
IMGO evaluation and remediation, especially in initial stages, should thoroughly inspect
the integrity of the structure and correct as necessary to prevent physical collapse.
7.5 Controlled substances
In the past, it was unusual to find “harder” drugs associated with MGOs and often the
growers prided themselves on being “organic farmers” and abstaining from other
controlled substances. More increasingly however, MGOs are production line facilities
designed for profit within the criminal world and the presence of other controlled
substances within a MGO is now common place. In fact, increasingly, where a MGO is
present, other clandestine drug operations may be simultaneously present.
8. Affected Professionals and Individuals by Stage of
Activity
The hazards that IMGOs present to emergency response personnel and other agency
personnel are varied and are primarily depend on the level of activity and exposure the
individual has to a specific IMGO. From first responders and health department
personnel to building inspectors and property owners, there are many who may be
exposed to hazards presented by IMGOs. The hazards associated with IMGO’s may be
different in each phase of activity. For the purposes of this guidance document, the
phases of IMGO response can be classified as:




8.1
Initial Response Phase
Assessment and Product Removal Phase
Remediation Phase
Re-Occupancy Phase
Initial Response Phase
Initial entry may be a planned visit as a result of an invitation by a land-lord or property
owner asking for a review or audit of a “legal” MGO, or it may be a response to an
otherwise unauthorized MGO.
The initial response phase consists primarily of first responders, including both law
enforcement and fire department personnel. The evaluation of potential hazards and
personal protective equipment during this phase is critical because there is usually little
information about the environment. Law enforcement and fire departments should
communicate their observations of hazards and sample results to subsequent entry
personnel. This information, in conjunction with observations of health and building
department officials, may be necessary to enforce local fire department code, building
code, OSHA regulations, or remediation requirements. This team approach will also
greatly reduce health and safety hazards associated with IMGOs.
8.1.1 Law Enforcement
Law enforcement agencies conduct operations at IMGOs in two broad operational areas:
tactical and evidence collection. Tactical operations are dynamic and aggressive in
nature and are usually designed to overwhelm any suspects or occupants inside the
structure. During initial tactical operations, speed and the ability to shoot, fight, or
otherwise restrain the occupants and suspects are paramount. The primary threats are the
suspects, other occupants, booby traps, and animals in the structure. Operators may be
armed, violent, unpredictable, and generally unwilling to turn over their operation to the
police. Law enforcement officers prepare for these dynamic situations by carrying
equipment that may include less-than-lethal armament, shields, thermal cameras, and
other items in addition to their standard ensemble.
The structural integrity of the building may have been compromised by the operators and
faulty electrical wiring may be present.
Transitioning from tactical operations to evidence collection operations may be a gradual
on-going transition rather than a distinct phase. Following the initial dynamic entry,
search and seizure operations begin wherein the premises is searched for evidentiary
purposes and booby traps and weapons are identified, secured, and subject to evidence
collection procedures.
Once the location has been entered by the police and the suspects and other occupants
have been secured, the operation moves to the evidence collection operation. Gathering
evidence is time consuming and must be carried out in a methodical approach. While
tactical operations may take minutes, evidence collection operations may take many
hours. At this time, photographs and videos are taken, sketches are made of the rooms
and the evidence within, legal forms filled out, interviews are conducted, and, the
marijuana growing operation is dismantled. Evidence collected can contain many hazards
that may include the plants themselves, chemicals, fertilizers, and electrical equipment.
Although contraband will be collected in its totality, chemicals, spills, and other hazards
may be left. Where evidence is needed from chemical supplies, the scene processing
team typically will only take small samples as evidence, leaving the bulk of materials on
scene. If chemicals or other hazards are identified as being unstable or otherwise posing
a threat to public safety, the situation will be stabilized as necessary with minimal
financial expenditure of tax-payer money.
8.1.2 Fire Department Personnel
Facilities used for marijuana grow operations also pose a hazard to firefighters in the
course of their work. While in some law enforcement scenarios there is information based
on drug trafficking investigations, fire department personnel are almost always
responding to an emergency or conducting inspections unrelated to clandestine drug
operations. Therefore, fire department personnel usually encounter marijuana grow
operations unexpectedly. Fire departments, or the local fire authority, have several
responsibilities beyond responding to fire related emergencies. These responsibilities can
either be emergency related or routine compliance inspections of “legal” grow
operations. Emergencies can include structural or wild land fires, odor complaints or
carbon monoxide complaints, first response to medical assistance, and hazardous material
releases.
Some fire departments may recognize the value of fire code inspection to assist in the
discovery of an unauthorized IMGO. Routine compliance inspections can include
industrial process permitting, occupancy permits, and home inspection programs for
smoke alarm compliance. Fire department personnel may also carry out fire
investigations to determine the cause, origin, and circumstances following a fire related to
an MGO.
During fire suppression activities, the most significant hazards remain those typically
encountered at other fire scenes (e.g. structural collapse, flashover, electrical hazards,
etc.). Operational priorities at this stage are victim rescue, firefighter safety, and fire
suppression activities. The nature of grow operations requires additional care and caution
due to the unique hazards they present. In most cases, standard structural fire fighting
practices and protective measures using universal precautions are adequate.
As with other fire scenes, tactical operations depend on an ongoing assessments during
the incident. Upon arrival, the initial scene assessment can glean certain indicators that
the structure may be used for marijuana grow operations. These indicators may provide
an early warning to firefighters of the unique hazards that may be encountered. Once
evidence of an IMGO is noted, fire personnel should deal exclusively with exterior fire
control and the evacuation of persons from the immediate area. These fires are considered
crime scenes and may need specialized hazardous material operations and training,
equipment, containment, and disposal procedures that may not be part of the fire
service’s capability or mandate. Law enforcement should be contacted concerning all
matters of illegal activity.
8.1.3 Precautionary Measures
[General Comment – I’m a little confused: NFPA 472 is “Standard for Competence
of Responders to Hazardous Materials/Weapons of Mass Destruction Incidents”
and I’m not sure what “A Guide for Mission Specific Response Tactics” is…. Is this
a subsection or chapter from NFPA 472?]
For example, the following measures should be employed by both law enforcement and
fire fighting personnel to minimize exposure




Wear the recommended PPE whenever working in the structure.
Minimize the number of people working in the structure.
Conduct administrative duties outside the structure.
Decontaminate personnel and equipment after inspection/investigation activities.


8.2
Use air monitoring equipment with oxygen and combustible sensors when
working in the grow-house.
Have self-contained breathing apparatuses (SCBAs) available (mandatory for fire
suppression activities).
Assessment and Product Removal Phase
The evaluation of hazards at this phase should include a thorough visual inspection and
air monitoring strategies. It is important to limit contact with surfaces, furniture,
miscellaneous items or product during the inspection process. When it becomes safe to do
so, windows and doors should be opened to allow fresh air into the structure. Directreading instrumentation can be used to quantify oxygen deficient atmospheres, high
levels of carbon dioxide and carbon monoxide, and other chemicals that may be present.
The limitations of direct reading must be recognized, however, since many of the
compounds that could be present in an IMGO may not be detected by many instruments.
colorimetric monitoring can be used to identify a multitude of hazardous air
contaminants. Limitations associated with this technology include inaccuracies up to +/35%, cross contamination, and the potential for false positives. [General Comments – in
general quantitative monitoring is not feasible and will not be performed. Rather
qualitative and semi-quant (such as colorimetric, electrochemical, PID/FID, GCAs,
etc.) will be used and are more appropriate. Unless someone can actually figure out
and document why first responders would be looking for mold, this statement
should be removed.]
[General Comments- This statement may be self conflicting since it is entirely
possible that spore concentrations outside may well excess those to which a first
responder may be exposed inside. Until such time that the committee is able to
support these positions with science, the irrational fear over mold sprees should be
removed. The document has already stated that the hazards, in general, are no
different than any other normal greenhouse – therefore, why are we not concerned
about mould spore concentrations in greenhouses? Answer: because there is no
science to support the argument that those exposures result in health hazards.]
Electrical hazards may be present inside and outside the structure. Testing of electrical
systems should be done with a non-contact voltage tester. Ensure that power to the
structure has been terminated—this may require assistance from local utility companies.
Be aware of temporary power supplies such as battery packs, capacitors associated with
ballasts, or generators. The breaker box should be located and visually inspected for
tampering. Extension cords, lamps, fans and other appliances should be unplugged.
8.3
Evaluation and Remediation Phase
After completion of evidence removal and the investigative phase by law enforcement
and other first responders, an IMGO should be evaluated for the presence of health and
safety hazards. There may be many different professional disciplines involved in property
evaluation and remediation, including building engineers, building code enforcement
personnel, industrial hygienists, and abatement specialists. Modification of electrical,
ventilation, and water distribution systems are common in IMGOs. The prevalence of
water and moisture can create severe hazards to those conducting remediation
evaluations.
During the remediation phase, additional hazards may be introduced into the structure.
Fortunately, these are known hazards and a job hazard analysis can be completed prior to
remediation activities.

Useful information can include:
o Information obtained from the assessment and product removal phases.
o Material safety data sheets for chemicals being introduced into the work
environment.
o Occupational or environmental monitoring that may have been completed
in the initial response or assessment and product removal phases.
o Pesticide labels.
o Previous personal protective assessments and requirements.
o Identification of the tools and equipment necessary to accomplish the
work.
Physical hazards associated with demolition and construction may include electrical
hazards, fall hazards, high noise levels, and hazards associated power tools. All electrical
hazards associated with the structure should be corrected prior to beginning remediation
work.
8.4
Re-Occupancy Phase
Re-occupancy should be delayed until remediation has occurred. This can be expensive
and time consuming for the property owner. When the property is owned by those
charged in connection with the IMGO, the solution is more difficult. These properties
commonly enter into foreclosure and may be owned by a bank.
In some jurisdictions, access to the properties may be restricted by local or county
officials and may not be released to the owner until the proper corrective actions have
been completed. Regulations pertaining to remediation requirements and release of
IMGO properties by public health officials are highly variable and subject to
jurisdictional requirements. Regulations continue to be developed at all levels of
government. In some cases, assessment and remediation documentation may be required
to be submitted to local governing agencies such as health departments or code
enforcement officers. Readers of this document are advised to consult with local
authorities regarding IMGOs.
It is important to document the remediation process in great detail, as those records may
follow the property from buyer to buyer. Depending on the jurisdiction, this information
may appear in property title searches. From the early stages of the preliminary assessment
to the remediation work plan and final clearance assessment, each of these processes
should be performed in accordance with applicable standards and documented as such.
Some of the elements that should be included in the final remediation documentation
include:





Background (e.g. circumstances that identified the property as an IMGO)
Preliminary assessment findings
Remediation recommendations (decontamination work plan)
Identification of remediation contractor, health and safety plans, and
description of decontamination processes
Results of final clearance assessment, including mold, asbestos, lead-inpaint sampling if conducted
8.4.1 Industrial Hygienists
Industrial hygienists (IHs) are experts in the recognition, evaluation, and control of
chemical and physical hazards. The training and qualifications of industrial hygienists are
ideal for the wide-ranging types of environmental health and safety hazards associated
with IMGOs. These hazards can include chemical hazards, airborne toxins, and
mold/moisture issues. IMGOs may be associated with other clandestine drug
manufacturing activities, including methamphetamine, ecstasy, PCP, or other synthetic
drugs. For more information on clandestine methamphetamine laboratory assessments,
AIHA has published the Clandestine Methamphetamine Laboratory Assessment and
Remediation guidance document.
Industrial hygienists can be involved in the initial response phase when assisting law
enforcement personnel during an enforcement action of an IMGO. Exposures to
chemical and physical hazards during this phase will likely be elevated. Industrial
hygienists, working with law enforcement and other first responders, can help in selection
of appropriate respiratory protection as well as other PPE. IHs can assist with
interpretation of air monitoring at the scene as well as assess the need for
decontamination of entry personnel.
Industrial hygienists are also involved in assessing contamination of a property and
assisting property owners in remediation efforts after an IMGO has been identified and
processed by law enforcement. Industrial hygienists can provide support relative to
chemical hazards, air contaminants, mold/moisture evaluations, and asbestos and lead
characterization surveys by performing sampling evaluations and developing remediation
plans. Industrial hygienists are also commonly employed to evaluate the effectiveness of
abatement prior to re-occupancy.
87.4.2 Remediation Contractor and Specialists
Remediation contractors are those companies and employees that conduct hazard
abatement of a property once it has been deemed an IMGO. Remediation may involve
removal of chemical and waste containers, the demolition of building materials,
asbestos/lead abatement, mold remediation and the removal of common household items
that may have become contaminated. Remediation specialists involved in IMGO
remediation should be trained and experienced in the handling of hazardous materials and
the use of PPE. Contractors should perform operations in accordance with applicable
regulations and a remediation plan prepared by an industrial hygienist.
8.4.3 Health Department Personnel
Health Departments may be involved in the initial response phase to determine onsite
hazards for law enforcement personnel although in many jurisdictions the role is unclear.
In lieu of specific regulations, health departments may be able restrict access to an IMGO
citing existing nuisance, unsafe property, or other ordinances. Health department
personnel may also enter the property to provide assistance to building code enforcement
personnel. Public health officials may assist property owners in potential regulatory
compliance issues related to IMGOs, including health department regulations, waste
disposal, mold remediation, and asbestos/lead regulations. Readers of this document are
advised to consult with their local health departments to determine regulatory
requirements pertaining to IMGOs prior to remediation of a property.
8.4.4 Building Code Enforcement
Like the health department, building officials may have the regulatory authority to
prevent entry pending remediation of the structure. Such officials play a key regulatory
role in ensuring an IMGO is returned to safe occupancy status. Non-occupancy orders
may be enforced until remediation is complete. These orders require the owner to acquire
all applicable permits and eventual reports declaring the structure safe for re-occupancy.
To make their determination, building officials may be required to enter the property to
assess structural, mechanical, and electrical issues. They are typically not trained in the
use of PPE or the exposure to potential environmental hazards and the hazards present in
IMGOs. Care must be taken to ensure that this is accomplished prior to entering the
property.
9. Personal Protective Equipment
Personal protective equipment is critically important to those that enter an IMGO. PPE
must be selected based on hazard identification and meet the physical demands of
entering a potentially hostile environment or an unknown atmosphere. Personal
protective equipment that does not fit properly, is uncomfortable, or does not provide the
necessary dexterity to complete required tasks may be worn improperly or not at all. PPE
must comply with health and safety standards. Specific training is required for hazardous
materials operations and respiratory protection.
Health and safety hazards prevalent in IMGOs can be broken down into the following
categories:
Physical Hazards are typically related to the structure that houses the IMGO and can
cause immediate physical harm to a person. They include electrocution, explosions or
booby traps, tripping hazards, and skin punctures. The property should be checked for the
presence of animals. Potentially dangerous animals should be secured or removed from
the site.
Contact Hazards (Dermal Hazards) can be associated with the structure and the
growing operation itself. Pesticides, and chemicals may all be present inside and outside
of the structure and may create serious health hazards for the unprepared.
Inhalation Hazards are typically byproducts of the growing operation. They include
pesticides, , dusts, gases, solvent vapors and others. It is important to fully understand the
limitations of respiratory protection. Powered and non-powered air purifying respirators
will not protect personnel from oxygen deficient atmospheres or hazardous levels of
carbon monoxide.
Hazardous Personnel may include the operators, occupants, associates, and customers
who may continue to arrive on scene even months after a MGO has been closed down.
There are three basic phases in the mitigation of an IMGO. These phases consist of the
Initial Response Phase, Assessment and Product Removal Phase, and the Remediation
Phase. For the purposes of this document, PPE recommendations are provided based on
the phase of the activity.
9.1 Initial Response Phase
Law enforcement and fire department personnel are involved in this phase. Each of these
disciplines provides tactical or operational personal protective packages for basic law
enforcement and fire fighting activities. The personal protective equipment listed here
compliments those packages and is not considered a replacement.
Personal protective equipment for the initial response phase should consist of:

Physical Hazards
o sturdy boots that are slip and puncture resistant and have non-conductive
soles
o eye and/or face protection
o tactical ballistic helmet
o tear and fire resistant outer garments

Contact Hazards
o chemical resistant gloves
o Tyvek® and/or chemical resistant coveralls
o chemical resistant boots

Inhalation Hazards
Exposures to any chemicals present must be evaluated prior to entry, and air purifying
respirators should only be used if the correct cartridges are available.
o Unknown atmospheres– NIOSH(CBRN)-approved Self-Contained
Breathing Apparatus (SCBA)
Note: The presence of occupants should not be an indicator of a safe atmosphere. Other
areas throughout the structure may contain IDLH conditions.
o Known atmospheres– NIOSH (CBRN)-approved powered air purifying
respirators or an air purifying respirator with a minimum P-100 cartridge
First responders should select PPE without regard to the size or number of plants in a
grow-house at the time of the seizure. [General Comments – either support the statement
with hard data and good science or remove].
9.2 Assessment and Product Removal Phase
Qualitative and quantitative analysis may be used when selecting personal protective
equipment during this phase. Particular attention should be given to any visual
observance of chemical containers, the location of the grow operation inside the structure
(i.e. below ground or above), and the overall condition of the grow operation.
Personal protective equipment for the Assessment and Product Removal Phase should
consist of:



Physical Hazards
o sturdy boots that are slip and puncture resistant and have non-conductive
soles
o eye and/or face protection
Contact Hazards
o chemical resistant gloves
o Tyvek® and/or chemical resistant coveralls
o chemical resistant boots
Inhalation Hazards
Exposures to any chemicals present must be evaluated prior to entry and air purifying
respirators should only be used if the correct cartridges are available.
o IDLH atmospheres must be eliminated prior to re-entry into the structure
for evidence collection and processing. If entry is required to confirm the
elimination of an IDLH atmosphere, a NIOSH (CBRN)-approved SCBA
should be worn.
o Known atmospheres– NIOSH (CBRN)-approved powered air purifying
respirators or air purifying respirator with a minimum P-100 cartridge.
Persons leaving the scene should undergo appropriate decontamination to remove trace
amounts of hazardous materials. Failure to do so can result in the contamination of clean
zones, emergency response vehicles, and co-workers completing tasks outside of the
IMGO.
9.3 Remediation
During the Remediation Phase there may be additional hazards introduced into the
structure. These are usually known hazards and a job hazard analysis should be
completed prior to remediation activities.
Particular attention should be given to respiratory hazards during the remediation phase.
Mold, dust, asbestos, lead, fiberglass, and other contaminants can become airborne during
remediation. In addition, chemicals used for decontamination, cleaning, repair, and
finishing work need to be evaluated. An industrial hygienist can be a valuable asset in
accurately characterizing potential air contaminants and health hazards.
A thorough job hazard analysis is critical during this phase. Clear identification of all the
hazards associated with the indoor grow operation will assist in identifying proper
engineering controls. These controls may reduce the level of personal protective
equipment needed.
Personal protective equipment for the Remediation Phase should consist of:

Physical Hazards
o sturdy boots that are slip and puncture resistant and have non-conductive
soles
o eye and/or face protection

Contact Hazards
o chemical resistant gloves
o Tyvek® and/or chemical resistant coveralls
o chemical resistant boots

Inhalation Hazards
A thorough hazard assessment that includes the evaluation of air
contaminants may eliminate the need for respiratory protection. IDLH
atmospheres should not be present during this phase of operation.
o NIOSH-approved air purifying respirators with appropriate cartridges
should be worn for chemicals introduced into the work environment if
exposure levels exceed established Occupational Exposure Levels (OELs).
OSHA maintains specific standards for respiratory protection pertaining to
asbestos, lead, and other airborne contaminants.
10 Remediation Issues
Remediation may be required to make the property habitable. The remediation process of
an IMGO property begins after law enforcement has completed site work, removed any
necessary evidence, and released the property to the owner. Some jurisdictions require
police to notify the local building or health department officials prior to leaving the scene
to allow unsafe occupancy notices to be posted.
Remediation/decontamination should be conducted in accordance with a written work
plan, typically generated by an industrial hygienist that clearly describes remediation
requirements, including lead and asbestos abatement issues, removal and disposal of
hazards or other chemicals, and correction of other deficiencies encountered. Electrical,
mechanical, structural, and plumbing repairs should also be addressed in a written plan,
with those requirements being generated by a qualified professional in those disciplines.
Remediation should be conducted in several phases whereby the most immediate hazards
are abated first. For instance, electrical hazards are addressed by disconnecting power to
the property to ensure that those correcting secondary hazards, such as structural repairs
are not exposed to electrical dangers. Temporary power can then be established for use
by other assessment and remediation personnel. A suggested sequence to follow in
remediation of an IMGO property is as follows:








Conduct preliminary assessment to determine remediation requirements and
generate a written work plan.
Cut-off power supply and establish temporary power under direction of licensed
electrician.
Ensure the structural integrity of the property to identify potential hazards such as
ceiling collapses, cave-ins, etc.
Conduct preliminary assessment to identify scope of remediation and generate
written remediation plan.
Establish work area boundaries and establish a regulated work area with
controlled access to authorized personnel only.
Erect any necessary containment barriers and engineering controls.
Remove hazardous chemicals, pesticides, fertilizers, etc. under controlled
conditions and dispose of in accordance with applicable waste disposal
requirements (may require profiling and waste characterization of unlabeled
containers).
Conduct hazard abatement (ie, asbestos, lead) as necessary and perform
associated clearance evaluation.

Correct building system deficiencies in compliance with building codes,
including structural, mechanical, electrical, and plumbing systems.
10.1 Preliminary Assessment and Remediation Work Plan
A preliminary assessment involves a physical evaluation of the structures involved in the
grow operation. This may involve an evaluation of the entire property grounds. It should
address removal and disposal of chemicals, fertilizers, pesticides, chemical and waste
containers, and contaminated soils. The assessment should also address moisture-related
issues at the property to include a comprehensive visual inspection of wall and ceiling
surfaces, attics and crawlspaces, and investigation of inner wall spaces where moisture
can accumulate.
Air monitoring should be performed initially to determine if the atmosphere in the IMGO
is safe. Real-time air monitoring with multi-gas detectors can identify the presence of
atmospheric hazards, including carbon monoxide, carbon dioxide, oxygen content, and
organic vapors. Air monitoring is also performed to determine the need for specialized
PPE during remediation.
The “Buddy System,” (at least two persons on site), is the preferred method of
conducting a preliminary assessment. There are many types of hazards that can be
encountered in IMGOs that are not commonly seen in other hazmat environments.
Examples include encounters with criminals, discovery of anti-personnel devices such as
fragmentation bombs, grenades, booby-traps (explosive devices, secondary incendiary
devices, hidden electrical triggers, refrigerator bombs, trip wires), razors, needles,
poisonous spiders and snakes, and biological hazards. Manufacturing of other drugs, such
as methamphetamine and ecstasy, may also have occurred, presenting another set of
potential hazards. Broken glassware and drug-use paraphernalia such as syringes or glass
pipes and cookware are also commonly encountered. These types of hazards must be
considered when conducting preliminary assessments.
Abatement of asbestos, and lead-based paint hazards and subsequent final clearance
procedures should be clearly described in the remediation work plan developed by the
industrial hygienist. The plan can then be distributed to the selected contractor(s) to begin
remediation.
10.2 Asbestos and Lead Remediation
Remediation of asbestos, and lead-based paint must be performed by qualified
professionals. Some remediation companies employ professionals and provide
comprehensive services that include mold, asbestos, and lead-in-paint abatement.
Asbestos and lead are governed by federal and state regulations. These regulations apply
to abatement within IMGOs. Some states and municipalities have enacted their own
regulations pertaining to mold, asbestos, and lead-based paint.
For more information pertaining to assessment and remediation of mold contamination in
buildings, readers of this document are referred to the following AIHA publications:

Assessment, Remediation, and Post-Remediation Verification of Mold Removal

Environmental Mold: State of the Science, State of the Art
10.3Post-Remediation Assessment
The post-remediation assessment should be performed to ensure that the environmental
health and safety hazards identified in the remediation work plan have been corrected. It
should include a physical assessment of the property similar to that conducted during the
preliminary assessment. The assessment should include the following elements:












Preliminary assessment information, including identification of the assessor,
sampling methods and results, extent of contamination, etc.
Property description, including physical address, number, and type of structures
present, description of adjacent and/or surrounding properties, and other relevant
observations.
Discussions and interviews with the owner.
[General Comment – while this would be useful information in the preliminary
assessment, I’m not sure I see the utility in post mitigation.)The remediation work
plan, including a description of chemical storage areas and waste disposal areas.
Identification of areas where contamination may have been spread, such as
common areas or adjacent spaces.
Identification of common ventilation systems serving multiple spaces or common
areas.
A description of health and safety procedures.
A description of decontamination procedures used and a description of each area
that was decontaminated.
A description of the removal procedures used and a description of areas where
removal was conducted, and the materials removed.
A description of any encapsulation procedures used and a description of areas
where encapsulation was conducted.
A description of the location and results of post-decontamination samples,
including a description of sample locations and a figure with sample locations and
identification, if any.
Photographic documentation of the property conditions before and after cleanup.
10.4 Building Infrastructure Remediation and Correction
Once hazards associated with the IMGO have been mitigated, building infrastructure
problems can be addressed. Professionals such as electricians, mechanical engineers,
structural engineers, and construction engineers may enter the property and address
deficiencies in their areas of expertise. This should include recommendations and actions
to bring these systems back to local building codes.
11 References
1. Alberta Solicitor General & Public Security: Marijuana – How can someone
spot a marijuana grow operation? Calgary, Alberta: Calgary Police Service, 2003.
2. U.S. Department of Justice: Domestic Cannabis Cultivation Assessment 2009.
U.S. Department of Justice. National Drug Intelligence Center. Document ID:
2009-L0848-001A, Washington, D.C.: National Drug Intelligence Center, 2009.
3. Cannabis Seed Banks: Grow Cannabis: Cannabis Grow Room Temperatures.
http://www.cannibis-seed-banks.com/index.html. [Accessed 11/11/2009].
4. Advanced Marijuana Grow Guide.
http://www.greenmanpage.com/guides/advanced.html. [Accessed 11/11/2009].
5. Dr. Goodbud's Growline. CO2 for the THC.
http://www.cannabisculture.com/backissues/cc05/goodbudco2.html. [Accessed
11/11/2009].
6. Nutrients and Marijuana Grown in Soil.
http://www.a1b2c3.com/drugs/mjgrow9e.htm. Accessed 11/11/09
7. Mustard, J., P. Hanson, and G. Wedman: Remediation of Former Marijuana
Grow Operations. Presentation at AIHce 2006. Chicago, IL: 2006.
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