Emergency Response to Terrorism:
Tactical Considerations: Hazardous Materials
Student Manual
Unit 5:
Protection
Terminal Objective

Given an exercise, the students will select appropriate
personal protective equipment (PPE) based on the
chemical and physical properties of the agent.
Enabling Objectives
The students will:

Identify the types and importance of respiratory
protection relative to a terrorist event.

Identify the advantages and risks involved with using
conventional PPE in a terrorist response.
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
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UNIT 5: PROTECTION
INTRODUCTION
As stated in Unit 1 Introduction, the focus of this training is protection and
detection. One of the key factors when responding to an incident
involving a biological, nuclear, chemical, or etiological agent is selecting
the proper level of protection for the incident. In the early days of
hazardous material response, there was a tendency to dress in Level A
protection without doing a complete risk assessment. A haz mat team
would respond to two drums of an unidentified product and would always
dress in Level A, yet our counterparts in the Environmental Protection
Agency (EPA) would respond to a hazardous waste site with hundreds of
drums on the site and would dress in Level C. This same mentality is
being applied to the Biological, Nuclear, Incendiary, Chemical, and
Explosive (B-NICE) arena of chemicals. These chemicals are being
produced by scientists working for various governments, with the intent to
kill hundreds of troops. Even with this knowledge, the military would
respond in mission-oriented protective (MOP) gear (Level C). Today,
some militant group mixes something in their basement and we, the
responders, jump into Level A. This section will provide you with the
knowledge to select the appropriate level of protection for the agent
involved.
THE IMPORTANCE OF RESPIRATORY PROTECTION
Respiratory protection is of primary importance since inhalation is one of
the major routes of exposure to chemical agents. Prior to discussing types
of respiratory protection, we must discuss the hazards that can affect the
respiratory system. Respiratory hazards fall into three general categories:
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airborne contaminants or aerosols;
inhalation of gases or vapors; and
oxygen-deficient atmospheres.
We will examine all three types of hazards and their associated physical
and physiological effects.
An airborne contaminant or aerosol is a suspension of a liquid or solid
particle in a gas. In the ambient air, it can take on various physical forms:

Dusts--contain solid particles suspended in the air.

Mists--the suspension of liquid particles formed by condensation
from vapors or by mechanical actions. Those actions can include
splashing of or atomization of the particles.
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
Fumes--suspended solid particles formed when a volatilized solid
condenses in cool air.

Fiber--suspended particle whose length is at least three times its
diameter.

Irritating smoke--an aerosol formed from the combustion of
organic matter.
The second type of respiratory hazard that could be encountered is gases
and vapors. A gas is defined as a state of matter that:
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can be expanded indefinitely;
mixes easily into other gases;
occupies most containers completely and uniformly; and
will expand or contract with temperature and pressures.
Vapors differ from gases in that they are normally solids or liquids at
standard temperature and pressure. When considering the type of
protection required, the type of gases and vapors must be considered.
The third type of hazard exists in oxygen-deficient atmospheres. The
normal content of oxygen in air at sea level is 21 percent. The
Occupational Safety and Health Administration (OSHA) states that an
atmosphere that contains 19.5 percent or less is considered immediately
dangerous to life and health (IDLH). As the oxygen decreases,
physiological effects will take place, and death can occur. Oxygen
deficiency can occur either as a result of lack of oxygen in an area,
resulting in simple asphyxiation, or because of the presence of chemicals
that, through a chemical change, leave the body unable to use oxygen.
This condition is called chemical asphyxiation.
TYPES OF RESPIRATORY PROTECTION
There are three types of respiratory protection:
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air-purifying respirators (APR's);
self-contained breathing apparatus (SCBA); and
Supplied-air respirators (SAR's).
Air-Purifying Respirators
When an incident occurs, according to current thought, tons of SCBA
units will be required. The necessity of refilling bottles either on site or
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off site, however, is a serious limitation that must be considered. In
reality, the hot zone most likely will be locked down as a crime scene,
with perhaps hundreds of people exiting the site, making offsite refilling
not a particularly viable option, and limiting the practicality of SCBA's for
all responders in such an incident. The protection of responders when
dealing with many injuries will require APR's.
APR's consist of several components designed to filter out airborne
contaminants through the use of filtration, absorption, or chemical
reaction. APR's have a role in B-NICE response, but can be used only
when the ambient atmosphere contains sufficient oxygen (19.5 percent).
They are approved for use in atmospheres containing specific chemicals
up to designated concentrations, but not in IDLH atmospheres.
Conditions that exclude or may exclude the use of APR's include

Oxygen deficiency.

IDLH concentrations of specific chemicals.

Entry into an unventilated or confined area where the exposure
conditions have not been characterized.

Presence of or potential presence of unidentified agents.

Contaminant concentrations that are unknown or exceed
designated maximum use concentration(s).

Identified gases or vapors that have inadequate warning properties,
when the absorbent's service life is not known and the APR unit
has no end-of-service indicator (ESLI).

High relative humidity (which may reduce the protection offered
by the absorbent).
Components of Air-Purifying Respirators
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full or partial facepiece;
filter/absorbent cartridge; and
exhalation valve.
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Advantages
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lightweight;
least expensive;
some are disposable; and
useful for support operations (e.g., patient decon, EMS, mass
decontamination).
Limitations
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become saturated with particles and other contaminants;
don't supply oxygen;
must have at least 19.5 percent oxygen to use;
can't be used with chemicals with poor warning properties; and
can't be used in IDLH atmospheres;
APR's usually operate only in the negative-pressure mode except for
powered air respirators, which maintain a positive pressure to the face
piece (except at maximal breathing rates). There are basically three types
of filtering devices:
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particulate filters;
cartridges or canisters that contain absorbents for specific gases
and vapors; and
combination devices.
Cartridges usually attach directly to the respirator facepiece. The larger
volume canisters attach to the chin of the facepiece or are carried with a
harness and attached to the facepiece by a breathing tube. Combination
cartridges and canisters contain layers of different absorbent materials and
remove multiple chemicals or multiple classes of chemicals from the
ambient air. Though approved for use against more than one substance,
these canisters and cartridges are tested independently against single
substances. Thus, the effectiveness of these canisters against two or more
substances has not been demonstrated. Filters also may be provided with
cartridges to offer additional protection against particulates. They are
color coded to indicate the general chemicals or classes of chemicals
against which they are effective. See the Code of Federal Regulations,
Title 29 (29 CFR) Part 1910.134.
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Color Coding for Cartridges
Contaminants
Acid gases
Hydrocyanic acid gas
Chlorine gas
Organic vapors
Ammonia gas
Acid gases & ammonia gas
Carbon monoxide
Acid gases & organic vapors
Hydrocyanic acid gas &
chloropicrin vapor
Acid gases, organic vapors, &
ammonia gas
Radioactive (except tritium & noble
gases)
Particulates w/any of above
All of the above atmospheric
contaminants
Color assigned
White
White w/1/2 green stripe
White w/1/2 yellow stripe
Black
Green
Green w/1/2 white stripe
Blue
Yellow
Yellow w/1/2 blue stripe
Brown
Purple (magenta)
Canister color w/gray stripe
Red w/gray stripe
Most chemical-absorbent canisters are imprinted with an expiration date.
They may be used up to that date as long as they have not been opened
previously. Once opened, they begin to absorb humidity and air
contaminants whether or not they are in use. Their efficiency and service
life decreases, and therefore they should be used immediately. Cartridges
should be discarded after use and should not be used for longer than one
incident or when breakthrough occurs, whichever comes first.
Where a canister or cartridge is being used against gases or vapors, the
appropriate device should be used only if the chemical(s) have "adequate
warning properties." The National Institute for Occupational Safety and
Health (NIOSH) considers a substance to have adequate warning
properties when its odor, taste, or irritant effects are detectable at
concentrations below the recommended exposure limit (REL). A
substance is considered to have poor warning properties when its odor or
irritation threshold is above the applicable exposure limit.
Warning properties are essential to the safe use of air purifying respirators
since they allow detection of contaminant breakthrough, should it occur.
While warning properties are not foolproof (because they rely on human
senses which vary widely among individuals and in the same individual
under varying conditions, e.g., olfactory fatigue), they do provide some
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indication of possible absorbent exhaustion, poor facepiece fit, or other
malfunctions.
Self-Contained Breathing Apparatus
A self-contained breathing apparatus (SCBA) usually consists of several
components carried by the wearer. Only positive-pressure SCBA's are
recommended for entry into IDLH atmospheres. SCBA's offer protection
against most types and levels of airborne contaminants. However, the
duration of the air supply is an important planning factor in SCBA use.
This is limited to the amount of air carried and the consumption rate of the
wearer. Also, SCBA's are bulky and heavy, thus they increase the
likelihood of heat stress, and may impair movement in confined spaces.
Generally, only workers handling hazardous materials or operating in
contaminated zones require SCBA's.
Entry and escape SCBA's give workers untethered access to nearly all
portions of the work site, but may decrease worker mobility, particularly
in confined areas, due to both the bulk and weight of the units. Their use
is particularly advisable when dealing with unidentified and unqualified
airborne contaminants.
Types of Self-Contained Breathing Apparatus
Open circuit: In the open circuit type, air is exhaled directly into the
ambient atmosphere. This is the most widely used type of SCBA.
Closed circuit: In the closed circuit type, exhaled air is recycled by
removing the carbon dioxide with an alkaline scrubber and replenishing it
with oxygen from a solid, liquid, or gaseous source. The advantages of a
closed circuit SCBA versus an open circuit are that they can have longer
durations of use (30 minutes to 4 hours) and are lighter in weight. On the
other hand, it is important to note that with a closed circuit type, the
wearer carries a hazardous material on his/her back (oxygen or an oxygengenerating chemical). Also, the chemical reaction that removes the carbon
dioxide causes the production of heat. This in turn can increase stress on
the wearer, especially in fully encapsulating chemical-protective suits.
Positive Pressure
The concept of positive pressure means that there is a constant pressure at
the facepiece of the SCBA at most times. This is created in most SCBA's
by allowing a small amount of air to bypass the regulator (slightly higher
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than atmospheric pressure). If there should be a leak in the face-to-facepiece seal or in the breathing tube, any airborne contaminant would be
pushed away from the wearer instead of being inhaled. It is important to
note that in some instances the wearer can breathe in a manner that
overpowers the positive pressure and causes airborne contaminants to be
inhaled through leaks in the system.
Advantages of SCBA's:
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highest level of respiratory protection,
wearer has good mobility; and
thirty minutes to 4-hour duration, which allows rotation of
personnel.
Disadvantages:

Air supply is limited; therefore work time is limited.

Weight of the unit (approximately 30 pounds).
Supplied-Air Respirator
Supplied-air respirators (SAR's; also known as airline respirators) supply
air, never oxygen, to a facepiece via a supply line from a stationary source.
SAR's are available in positive- and negative-pressure modes. Pressuredemand SAR's with escape provisions provide the highest level of
protection (among SAR's) and are the only SAR's recommended for use at
hazardous waste sites. SAR's are not recommended for entry into IDLH
atmospheres unless the apparatus is equipped with an escape SCBA.
Advantages:
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offer high level of respiratory protection;
can be used for extended periods of time; and
lighter than SCBA's and may place less stress on the wearer.
Disadvantages:

Air must enter and exit via same path.

Airline restricts mobility.

Maximum hose length of 300 feet.

Airline hoses are not tested for chemical resistance.
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The air source for supplied-air respirators may be compressed air cylinders
or a compressor that purifies and delivers air to the facepiece. SAR's
suitable for use with compressed air are classified as "Type C" SAR's. All
SAR couplings must be incompatible with the outlets of other gas systems
used on site to prevent a worker from connecting with an inappropriate
compressed gas source (OSHA 29 CFR 1910.134).
SAR's enable longer work periods than the SCBA's and are less bulky.
However, the airline impairs workers' mobility and requires workers to
retrace their steps when leaving the area.
Also, the airline is vulnerable to puncture from rough or sharp surfaces,
chemical permeation, damage from contact with heavy equipment, and
obstruction from falling drums, etc. To the extent possible, all such
hazards should be removed prior to use. When in use, airlines should be
kept as short as possible (300 feet [100 meters] is the longest approved
hose length for SAR's), and other workers and vehicles should be kept
away from the airline.
The use of air compressors as the air source for an SAR at a hazardous
waste site is severely limited by the same concern that requires workers to
wear respirators--that is, the questionable quality of the ambient air. Onsite compressor use is limited by OSHA standards (29 CFR Part
1910.134).
CONVENTIONAL PERSONAL PROTECTIVE EQUIPMENT
In the realm of PPE, responders traditionally have believed that the best
protection from agents were the garments that were provided to the
military. Recently, many governmental response agencies have been
looking at the more conventional garments worn by responders for most
chemical incidents. As a review, let's examine the levels of protection as
outlined by the EPA.
Level A
Level A protection is required for entry into areas of very high
contamination that pose risks of inhalation, skin, mucous membrane, and
eye exposure. This level of protection is required for toxic environments
that exceed the IDLH level and for prolonged work at contamination
levels greater than the STEL.
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To achieve Level A protection, PPE must include at least:
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positive-pressure SCBA or positive-pressure air;
line with escape options;
fully encapsulating chemical-resistant suit;
double layer of chemical-resistant gloves;
chemical-resistant boots;
airtight seals between the suit and the gloves and boots; and
communications.
Level B
Level B equipment provides respiratory protection comparable to that of
Level A, but less protection against skin, mucous membrane, and eye
exposures. Level B PPE suits are chemical resistant and offer protection
against splash exposures. They may be fully or nonencapsulating and
allow vapor and dust to enter at the neck, wrists, and closures. Level B
protection is the minimum level that should be used for entry into a BNICE site that has not been tested and monitored fully.
To achieve Level B protection, PPE must include at least:
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positive-pressure SCBA;
chemical-resistant, long-sleeved suit;
double layer of chemical-resistant gloves;
chemical-resistant boots;
hard hat; and
communications.
Level C
Level C equipment is appropriate for use when the agents have been
identified, their concentrations in air are known to fall within the effective
range of air-purification filters, and there is little likelihood of exposure of
the skin, mucous membranes, or eyes.
To achieve Level C protection, PPE must include at least:
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full-face air-purification device (respirator);
chemical-resistant suit;
chemical-resistant outer gloves; and
chemical-resistant boots.
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Level D
Level D equipment is essentially common work clothes that do not
provide specific respiratory or skin protection. This level of PPE should
not be worn alone in any environment that poses a hazardous materials
risk as a result of respiratory, skin, mucous membrane, or eye exposure.
Military Protective Ensembles
Individual Protective Equipment
A soldier's mission-oriented protection posture (MOPP) gear protects
against NBC contamination. It consists of the overgarment, mask, hood,
overboots, protective gloves, individual decon kits, detection equipment,
and antidotes. Before soldiers can protect themselves against nuclear,
biological, and chemical (NBC) hazards, they must first know what
individual protective equipment is available and its capabilities.
Protective Ensemble
Various armies of the world use different types of chemical-protective
clothing for individual protection. Several types are available in the U.S.
Army. The type depends on the protection required, but all fall within two
major divisions: permeable and impermeable. Permeable clothing allows
air and moisture to pass through the fabric. Impermeable clothing does
not. An example of impermeable clothing is the special butyl rubber suits
worn by some explosive ordnance disposal (EOD) soldiers and decon
soldiers. Most troops use permeable suits known as battledress
overgarments (BDO's).
Battle Dress Overgarment
Description
The BDO is a camouflage-colored (woodland or desert), expendable twopiece overgarment consisting of one coat and one pair of trousers. The
jacket has a zipped front, and the trousers have a fly front and zipped legs.
The overgarment material consists of an outer layer of nylon/cotton and an
inner layer of charcoal-impregnated polyurethane foam. Due to the heavy
impregnation of charcoal, some charcoal may be deposited on skin and
clothing under the BDO; however, this will not detract from the BDO's
chemical-protective characteristics nor harm the wearer. The BDO
presently comes sealed in a vapor-barrier bag that protects against rain,
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moisture, and sunlight. The BDO is water resistant, but not waterproof,
and normally is worn as an outer garment over the duty uniform; however,
in high temperatures it may be worn over underwear. In extreme cold
weather environments, the BDO is sized to wear over Arctic/extreme cold
weather environmental clothing; however, mission requirements may
dictate that the BDO be worn under Arctic clothing. For example, soldiers
may need to wear a white Arctic outergarment to help ensure needed cover
and concealment.
Protection Capabilities
The BDO provides protection against chemical agent vapors, liquid
droplets, biological agents, toxins, and radioactive alpha and beta
particles. When the BDO is removed from its vapor-barrier bag and worn,
its protective qualities last for a minimum of 30 days. It is recommended
that the BDO be replaced after 30 days; however, the commander may
extend the wear time when operationally necessary. BDO's worn longer
than 30 days present a slightly increased risk to the wearer; however, the
key to BDO effectiveness at any time during wear is its serviceability.
Wear time for the BDO begins when it is removed from its sealed vaporbarrier bag, and stops when the BDO is sealed back in its vapor-barrier
bag. If the original vapor-barrier bag is not available, return the BDO to a
bag of similar material and seal with common duct tape. Donning of the
BDO regardless of the length of time equates to a day of wear. Extending
the wear time for the BDO affords additional flexibility in operational and
logistical support planning. The BDO provides a minimum of 24 hours of
protection against exposure to liquid or vapor chemical agent. Exchange
the BDO within 24 hours of exposure to a liquid chemical agent. The
BDO is not designed to be decontaminated or reimpregnated for reuse.
Serviceability
The BDO becomes unserviceable if it is ripped or torn, if its fastener is
broken or missing, or if petroleum, oils, or lubricants are spilled or
splashed on the garment. For example, if a product spills on a BDO sleeve
or trouser leg and soaks through the BDO material, replace the BDO.
Further, the BDO remains serviceable if the vapor-barrier bag suffers
damage (i.e., pinholes, rips, tears), provided the overgarment has not been
physically damaged or exposed to water, spills, or chemical agents. When
any packaging leaks are discovered, seal/repair them as soon as possible.
Common duct tape provides an appropriate and expedient way to repair
the vapor-barrier bag. Sealing the bag protects the BDO from direct
exposure to moisture, smoke, and fuel solvent vapors which can
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jeopardize the BDO protective qualities; however, if the original vaporbarrier bag is no longer available to the soldier for overgarment storage,
use a replacement storage bag that, as a minimum, is water resistant or
water repellent.
Chemical Protective Overgarment
Description
The CPOG is a plain OD green, expendable two-piece overgarment
consisting of one coat and a pair of trousers. The jacket has a full-length
zipper opening covered by a protective flap. The trousers have a fly front
and zipper closure on the lower outside section of each leg. The CPOG is
made of material having an outer layer of nylon/cotton and an inner layer
of charcoal-impregnated polyurethane foam. Due to the heavy
impregnation of charcoal, some charcoal will be deposited on the skin and
clothing under the overgarment; however, this will not detract from the
chemical-protective characteristics of the suit nor harm the wearer. The
CPOG comes sealed in a vapor-barrier bag that protects against rain,
moisture, and sunlight. To protect the protective qualities of the CPOG
against rain, wet-weather gear should be worn over the overgarment. The
CPOG is normally worn over the duty uniform; however, in high
temperature it may be worn over underwear. In extreme cold weather, the
CPOG is sized to wear over Arctic extreme cold weather environmental
clothing; however, mission requirements may dictate that the CPOG be
worn under Arctic clothing. For example, soldiers may need to wear a
white Arctic outer garment to help ensure needed cover and concealment.
Protection Capabilities
The CPOG provides protection against chemical agent vapors, liquid
droplets, biological agents, toxins, and radioactive alpha and beta
particles. When the CPOG is removed from its vapor-barrier bag, its
protective qualities last for a minimum of 14 days. It is recommended that
the CPOG be replaced after 14 days; however, the commander may extend
the wear times when operationally necessary. CPOG's worn longer than
14 days present a slightly increased risk to the wearer; however, the key to
CPOG effectiveness at any time during its wear is its serviceability.
Wear time for the CPOG begins when it is removed from its sealed vaporbarrier bag, and stops when the CPOG is sealed back in its vapor-barrier
bag. If the original vapor-barrier bag is not available, return the CPOG to
a bag of a similar (i.e., waterproof) material and seal with common duct
tape (for example, double plastic trash bags are a possibility). Donning of
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the CPOG, regardless of the length of time, equates to a day of wear.
Extending the wear time for the CPOG affords additional flexibility in
operational and logistical support planning. The CPOG provides a
minimum of 6 hours of protection against exposure to liquid or vapor
chemical agents. Exchange the CPOG within 6 hours of exposure to a
liquid chemical agent. The CPOG is not designed to be decontaminated or
reimpregnated for reuse.
Serviceability
The CPOG becomes unserviceable if it is ripped or torn, if its fasteners are
broken or missing, or if petroleum, oils, or lubricants (POL) are spilled or
splashed on the garment. For example, if a POL spill on a CPOG sleeve
or trouser leg soaks through the CPOG material, replace the CPOG.
Further, the overgarment remains serviceable if the CPOG vapor-barrier
bag suffers damage (i.e., pinholes, rips, tears), provided the overgarment
has not been physically damaged or exposed to water, spills, or chemical
agents. When any packaging leaks are discovered, seal/repair them as
soon as possible. Common duct tape provides an appropriate and
expedient way to repair the vapor-barrier bag. Sealing the bag protects the
CPOG from direct exposure to moisture, smoke, and fuel solvent vapor
which can jeopardize the CPOG's protective qualities; however, if the
original vapor-barrier bag is no longer available to the soldier for
overgarment storage, use a replacement bag that, at a minimum, is water
resistant or water repellent. For example, the waterproof bag can be used
for storage.
Contamination Avoidance and Liquid Protective Suit
The suit, contamination avoidance and liquid-protective (SCALP), is a
four-piece suit consisting of jacket, trousers, and two footwear covers.
The base cloth material is of high-density polyethylene fibers, and the
footwear covers have embossed polyethylene soles for durability and slip
resistance. The jacket is a pullover design with an integral hood and
covers the head, chest, and arms. An opening is provided for the facepiece
of the individual protective mask. Two drawstrings, each with a
barrelock, secure the hood to the facepiece, and latex bands secure sleeves
around the wrists. The trousers contain a drawstring with a barrelock at
the waist and latex bands on the legs to secure them around the ankles.
The footwear covers consist of polyethylene soles and latex bands in the
upper portion to secure them to the legs. The SCALP jacket/trousers are
issued separately from the SCALP footwear covers, since the sizing
systems are independent of one another. The SCALP, being a disposable,
lightweight, impermeable suit, is to be worn on the outside to keep from
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gross liquid contamination for periods up to 1 hour. The primary users are
armor and EOD personnel and personnel in collective protection who
may, by necessity, be forced to leave that collective protection to perform
some vital maintenance or reconnaissance function. In such situations, the
SCALP also will reduce reentry time. A secondary use of the SCALP is
to protect decontamination personnel from being soaked during
decontamination operations. Commanders must be aware that wearing the
SCALP over the BDO will place an additional burden on the soldier,
increasing heat stress problems already associated with wearing the BDO.
The SCALP weighs approximately 1.5 pounds.
Integrated Battlefield Aircrew Uniform
The aircrew uniform, integrated battlefield (AUIB), is a standard combat
uniform for aircrews designed to replace the CPOG, BDO, and Nomex
flight suit. The AUIB provides NBC protection and protection against
flames. It is a two-piece chemical-protective uniform with a protective
curtain and stand-up collar. The collar closes with a hook-and-pile tape.
The suit has a slide fastener front closure with protective flap and a
gusseted fastener leg closure for quick and easy donning and doffing. The
wrists and ankles have hook-and-pile adjustments to ensure a tighter fit.
Chest pockets are side openings for easy access when the safety harness is
in use. Side thigh and calf pockets have bellows on one side for easy
access. Insulated pockets for atropine injectors are provided on the upper
sleeve. All pockets are lined with butyl rubber.
Toxicological Agent Protective Apron
The toxicological agent protective (TAP) apron is intended for personnel
whose duties may bring them into contact with liquid chemical agents: for
example, those who work with toxic munitions, perform decontamination
in a field environment, handle contaminated clothing and equipment at a
decontamination site, and handle and treat chemical agent casualties. On
the battlefield, the TAP apron provides chemical decontamination units
with added protection when conducting extended decontamination
operations.
Chemical Protective Clothing Selection Criteria
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
Have you identified the agent involved and determined its
physical, chemical, and toxicological properties?

Does the product have a high vapor pressure?
UNIT 5: PROTECTION
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At the concentrations expected, is the substance a skin hazard?

Select the material which provides the least permeation and
degradation.

Determine whether a fully encapsulating suit is required or if nonencapsulating is sufficient.
In those incidents where the presence of the agent is not certain or the
agent cannot be readily identified, there usually are clues that can assist in
choosing the level of protective clothing. Observations which could
indicate that fully encapsulating suits should be worn are
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visible emissions of gases, vapors, dust, or smoke;
indications of airborne hazards on direct-read instruments;
configurations of containers or vehicles that indicate they contain
gases or pressurized liquids;
enclosed, poorly ventilated areas where toxic vapors, gases, and
other airborne substances could accumulate; and
work functions required that might expose workers to high
concentrations of skin toxins.
Unknown situations require considerable judgment as to whether
maximum protection to the skin (fully encapsulating clothing) is necessary
or whether splash suits are appropriate.
Heat stress: Nonencapsulating clothing generally causes less heat stress.
However, as less area of the body is exposed by wearing gloves and hoods
and taping hoods to respirator masks, there is little difference in the heat
buildup of either style.
AGENT-SPECIFIC PERSONAL PROTECTIVE EQUIPMENT/CHEMICAL
PROTECTIVE CLOTHING MATRIX
Biological agents enter the body through the respiratory tract, digestive
tract, and breaks in the skin. A HEPA filter accompanied by Level C
clothing provides adequate protection against all biological agent threats.
Radiological agents may enter the body through the respiratory tract, the
digestive tract, and breaks in the skin (or in the case of gamma radiation,
through the skin). A high-energy air particulate (HEPA) filter
accompanied by Level C clothing provides adequate protection against
alpha and beta radiation exposure hazards (the respiratory tract, digestive
tract, or breaks in the skin).
SM 5-17
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
Nerve agents (e.g., Tabun, Sarin, Soman, VX) present both a respiratory
and a dermal hazard. In liquid form, droplets may be absorbed by the
skin; in a vapor state, they may enter the body through the lungs.
Blister agents (e.g., mustard) are designed to cause both internal and
external injury. With both a dermal and respiratory threat, protection is
required for each route of entry.
Choking agents (e.g., phosgene, chlorine) enter the body through the
lungs, but may harm the skin; consequently, respiratory protection is the
key to protection in a choking agent environment.
Choking agents are reasonably nonpersistent, so the level of protection
may be downgraded (1) as soon as the concentration in the affected area is
determined to be below IDLH and, (2) if the respirator to be used has been
proven to protect against the particular choking agent.
Blood agents (e.g., hydrogen cyanide, cyanogen chloride) enter the body
primarily through membranes and at high levels through the skin. Since
blood agents, by definition, are extremely volatile, they will dissipate
quickly in the air, probably by the time measurements are taken to
determine the concentration of the agent. If the agent vapor concentration
is below IDLH, the level of protection required may be downgraded, but
as with choking agents, only if the respirator to be used is known to
protect against the particular blood agent.
SM 5-18
UNIT 5: PROTECTION
It is common belief that hydrogen cyanide is a skin-absorbable toxin. Although this is
partially true, the following provides some information that is not commonly known
about hydrogen cyanide (HCN). The most common form of cyanide is a solid, but
HCN is found as a liquid, and as a gas. When in liquid form the concentration varies
between 2 percent and 99.5 percent. One of the problems with chemical information
found with research texts is that typically it is for one form of the material, but the
hazards that one form may present may not apply to another form. The exposure
limits are as follows STEL--4.7 ppm, threshold limit value (TLV)--10 ppm, LCLo-200 ppm/5 mins. The skin-absorbable toxicity of cyanides generally comes from
contact with the solid material. Through studies it is known that normal healthy
humans have 0.5 mg/kg in their bodies most of the time. After an exposure, the halflife of cyanide in a human is 20 minutes to 1 hour. Studies also have shown that
concentrations above 90 ppm can be fatal, and that 45 ppm can cause diverse
symptoms. One experiment used a 12 kg dog and a 70 kg man who were exposed to
HCN in a chamber containing 500 to 635 ppm. The dog began to show symptoms at
50 seconds, was unconscious in 75 seconds, and developed respiratory arrest at 93
seconds. At 91 seconds the man had no symptoms and left the chamber. After 3 to 8
minutes he developed minor symptoms, which continued for a period of time. The
dog was left and assumed to be dead, but 12 hours later was found to have recovered
with no lasting effects. All of the previous exposures included both skin and
respiratory routes. Some testing was done specifically on skin absorption alone. Dogs
were tested, and an exposure of 15,200 ppm HCN for 47 minutes was fatal to the
dogs. However an exposure of 5,000 ppm for 180 minutes showed no effects. In one
incident several workers were exposed while wearing gas masks and no other
protective clothing. They were in the atmosphere for 8 to 10 minutes. They were
incapacitated for 2 to 3 days but recovered without any apparent effects. They were
exposed to 20,000 ppm, which is a considerable amount. This incapacitation suggests
that HCN is toxic by skin absorption, but requires a high level to cause any effects. It
can be derived then that your level of PPE should consider the amount present in the
atmosphere. If persons without PPE of any type are alive (even symptomatic) within
a given environment, then a responder with respiratory protection and some other type
of PPE (chemical suit--A, B, C, or TOG) has more than adequate protection to make a
rescue. (Information obtained from NIOSH report 77-108, Biological effects of
exposure to hydrogen cyanide.)
SM 5-19
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
SM 5-20
UNIT 5: PROTECTION
Activity 5.1
Selecting PPE
Purpose
To provide insight into selecting appropriate PPE based on the chemical and physical
properties of the agent involved.
Directions
1.
Work in small groups.
2.
Read through the five MSDS's and the permeation chart provided in this
exercise.
3.
For each agent, indicate the level of chemical and respiratory protection that
would be best suited for an incident involving that agent.
4.
The amount of chemical is less than 1 gallon and the haz mat team is going in
to sample the material. The weather is cloudy, 68F (20ºc), wind is 3 mph,
and humidity is 70 percent.
5.
Document the factors you used when making your decisions on level of
protection.
6.
A spokesperson from your group will read your answers and list of factors
considered to the rest of the class. Be prepared to explain your reasoning.
SM 5-21
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
Agent A
Description
Vapor pressure
Volatility
Vapor density
Specific gravity
Melting point
Ionization potential
Boiling point
Route of entry
Effects
Symptoms
Reacts
Decomposes
Solubility
Protection
Detection devices
Treatment
Decontamination
PEL
TLV
STEL
LD50
LC50
IDLH
LCt50
ICt50
SM 5-22
Greenish-yellow gas
5,000 mm/Hg
20,000,000 mg/m3
2.5
-67F (-55ºC)
-33F (-36.ºC)
Respiratory
Immediate
Strong eye, throat, and mucous membrane irritation,
coughing, choking, tightness in chest
With many substances, is a corrosive and an oxidizer
Slightly in water
Respiratory
pH, colorimetric tubes, Agent A electrochemical gas sensor
Remove from environment, fresh air
Fresh air, flush with water if contaminated with liquid
0.5 ppm
0.5 ppm
1 ppm
10 ppm
~6500 ppm 1 min.
~600 ppm
UNIT 5: PROTECTION
Agent B
Description
Vapor pressure
Volatility
Vapor density
Specific gravity
Melting point
Ionization potential
Boiling point
Route of entry
Effects
Symptoms
Reacts
Decomposes
Solubility
Protection
Detection devices
Treatment
Decontamination
PEL
TLV
STEL
LD50
LC50
IDLH
LCt50
ICt50
Brown liquid
2.9 mm/Hg @ 25C (77ºF)
20,000 mg/m3 @ 25C
5
1.07
-70F (56.7ºC)
<10.6 eV
310F (154ºC)
Respiratory, skin absorption
Immediate
Runny nose, tightness of the chest, gastrointestinal
symptoms will appear first
Stable
Quickly in acids and alkalis, slowly in water; decomposes
in 3 hours at 302F (150ºC)
Slightly in water, more in organic solvents
Respiratory and skin
Basic life support, decontamination
Fresh air, flush with water if contaminated with liquid
0.000017 ppm
9.3 mg/kg
0.03 ppm
12 ppm
8 ppm
SM 5-23
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
Agent C
Description
Vapor pressure
Volatility
Vapor density
Specific gravity
Melting point
Ionization potential
Boiling point
Route of entry
Effects
Symptoms
Reacts
Decomposes
Solubility
Protection
Detection devices
Treatment
Decontamination
PEL
TLV
STEL
LD50
LC50
IDLH
LCt50
ICt50
SM 5-24
Colorless liquid
760 mm/Hg @ 100C (212ºC)
22,933 mg/m3
1
1
34F (1.1º)
12.4 eV
100C or 212F
Ingestion, respiratory
Delayed
Convulsions, tremors, loss of muscle control
With many substances, can release hydrogen during a
reaction
Into hydrogen
In water
Respiratory
Remove from environment, fresh air
Fresh air, flush with water if contaminated with liquid
25 g/Kg
UNIT 5: PROTECTION
Agent D
Description
Vapor pressure
Volatility
Vapor density
Specific gravity
Melting point
Ionization potential
Boiling point
Route of entry
Effects
Symptoms
Reacts
Decomposes
Solubility
Protection
Detection devices
Treatment
Decontamination
PEL
TLV
STEL
LD50
LC50
IDLH
LCt50
ICt50
Colorless to brown liquid
0.11 mm/Hg @ 25C (77ºC)
600 mg/m3
5.5
57F (13.9ºC)
<10.6 eV
423F (217.2ºC)
Skin
Delayed
Burning of skin
0.0005 ppm
0.0005 ppm
231 ppm
23 ppm
SM 5-25
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
Agent E
Description
Vapor pressure
Volatility
Vapor density
Specific gravity
Melting point
Ionization potential
Boiling point
Route of entry
Effects
Symptoms
Reacts
Decomposes
Solubility
Protection
Detection devices
Treatment
Decontamination
PEL
TLV
STEL
LD50
LC50
IDLH
LCt50
ICt50
SM 5-26
Colorless gas
1,180 mm/Hg
6,000,000 mg/m3
3
-288F (-177.8ºC)
46F (7.8ºC)
Respiratory
Immediate for high levels, delayed for lower levels
Coughing, choking, tightness in chest
With water
Slightly in water
Slightly in water, soluble in benzene and acetic acid
Respiratory
Remove from environment, fresh air
Fresh air, flush with water if contaminated with liquid
0.1 ppm
0.1 ppm
2 ppm
800 ppm
400 ppm
UNIT 5: PROTECTION
Permeation Chart
Agent
Suit 1
Suit 2
Suit 3
Boot 1
Boot 2
Glove 1
Glove 2
A
B
C
D
E
>50
>20
>480
>480
NT
>480
255
>480
NT
29
>480
<20
>480
>183
>480
35
>480
>480
NT
60
>480
120
100
300
300
>8
>480
1
>480
250
>480
240
>480
5
NT
SM 5-27
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
SM 5-28
UNIT 5: PROTECTION
Selecting PPE Worksheet
Agent
A
B
C
D
E
Level-Suit
Suit
Boot
Gloves
Chemical
General Factors Considered
Specific Factors Considered
Agent A:
Agent B:
Agent C:
Agent D:
Agent E:
Notes
SM 5-29
EMERGENCY RESPONSE TO TERRORISM: TACTICAL CONSIDERATIONS: HAZARDOUS
MATERIALS
SM 5-30