CHEMICAL CARCINOGENS
What is a carcinogen?
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Any substance that is capable of causing cancer.
Cancer is the abnormal or uncontrolled growth of new cells
in any part of the body, characterized by cells that tend to
invade surrounding tissue and metastasize to new body
sites.
Carcinogens are chronic toxins. They cause damage after
repeated or long-duration exposure. They may have not
immediate apparent harmful effects, with cancer
developing only after a long latency period.
What are reproductive toxins?
 Mutagens
cause damage to chromosomes by introducing
changes to DNA.
 Mutagens have adverse
effects on fertility and
general reproductive
performance.
 Mutagens are chronic
toxins
 Teratogens
act during pregnancy to
cause adverse effects on
the embryo or fetus
including malformations,
retarded growth and postnatal deficiencies.
 Reproductive toxins can
affect both men and
women.
What materials are carcinogens?
 Asbestos
 Certain
chemicals
 Coal tars and coke oven emissions
 Hardwood sawdust (certain species)
 Ionizing radiation
 Natural products (progesterone, safrole)
 Tobacco smoke
 Ultraviolet radiation
What is a chemical carcinogen?
 Any
discrete chemical compound which has
been shown to cause cancer in human or
animal studies.
 Hundreds of individual compounds have
been shown to induce cancers. Many
thousands of additional compounds are
“suspect” carcinogens.
 Many are commonly used in laboratory
operations, shops and art studios.
How is chemical carcinogenicity determined?
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Epidemiological studies determine the relationship
between a cancer suspect chemical and a human
population over a long period of time.
Animal studies directly induce cancer in test animals using
a large sample of animals, usually of two or more species
with varying dose and time parameters.
Experiments with animals are based on the premise that
chemicals that produce cancer in animals will have similar
effects on human cells. Most known human carcinogens
produce cancer in experimental animals.
What is an OSHA “select” carcinogen?
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Any substance that is regulated by OSHA as a carcinogen.
It is listed under the category “know to be carcinogens” in
the Annual Report on Carcinogens published by the
National Toxicology Program (NTP).
It is listed under Group 1 (“carcinogenic to humans”) by
the International Agency for Research on Cancer (IARC).
It is listed in either Group 2A (“limited evidence of
carcinogenicity” from human studies) or 2B (“sufficient
evidence of carcinogenicity” from animal studies) by
IARC or under the category “reasonably anticipated to be
carcinogens by NTP. (A specified dose range is given.)
Which classes of chemicals tend to be carcinogens?
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Epoxides:
Ethylene oxide
Propylene oxide
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Hydrazines:
Hydrazine (and salts)
1,2-Dimethylhydrazine
N-Nitroso compounds:
N-Nitrosodimethylamine
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Organohalogen comp.:
Vinyl chloride
Carbon tetrachloride
Chloroform
Hexachlorobenzene
Trichloroethylene
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Aromatic Amines:
Benzidine
Aniline
o-Anisidine
o-Toluidine
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Aromatic hydrocarbons:
Benzene
Benz[a]anthracene
Benzo[a]pyrene
Classes of carcinogens (cont.)
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Misc. organic compounds:
Formaldehyde
Acetaldehyde
1,4-Dioxane
Ethyl carbamate
2-Nitropropane
Styrene
Thiourea
Thioacetamide
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Misc. inorganic comp.:
Arsenic and compounds
Chromium and comp.
Thorium dioxide
Beryllium and compounds
Cadmium and compounds
Lead and compounds
Nickel and compounds
Selenium sulfide
How do carcinogens enter the body?
 Skin
absorption. Many solvents and other
chemicals go directly through the skin.
 Ingestion. Swallowing of a carcinogen.
 Inhalation. Breathing gases, fumes and
vapors is the most common form of
exposure.
What organs to carcinogens attack?
 Lungs
 Liver
 Kidney
 Reproductive
system
 Skin
 Many
other organs and tissues
What factors influence the development of cancer?
 Dose--amount
and length of exposure. The lower
the dose the least likely you are to develop cancer
or related diseases.
 Environmental or “lifestyle” factors.
 Cigarette
smoking (co-carcinogen)
 Alcohol consumption (co-carcinogen)
 Diet--high fat consumption, natural antioxidants
 Geographic location--industrial areas, UV light
 Therapeutic drugs--some are known carcinogens
 Inherited conditions
How do I reduce my exposure to carcinogens?
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Engineering controls--exhaust ventilation and equipment
Personal protective equipment
Personal hygiene
Labeling and storage of containers
Housekeeping and maintenance
Regulated areas
Decontamination and emergency procedures
Monitoring
Administrative controls
Engineering controls--exhaust ventilation and equipment
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General room ventilation--10 or more changes of air per
hour. Designed to reduce exposures below the permissible
exposure limit (PEL). Many carcinogens have a very low
exposure limit. Use an “ALARA” policy.
Fume hoods--full open face velocity of 8o to 100 l.f.p.m..
combined with a dry ice capture test.
Local ventilation--exhaust (sometimes supply) at the point
of use of a chemical. “Elephant trunk” or slot hood.
Carcinogen glove box or environmental chamber.
Biosafety cabinet--used for anticancer drugs, viruses.
No benchtop work in a laboratory setting.
Personal protective equipment
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Respiratory protection--dust masks, respirators.
Respirators are primarily for use in non-lab areas, except
for emergency response (spill cleanup)--shops, floor
stripping, construction operations (painting).
Eye protection--safety glasses, splash goggles, face
shields.
Hand protection--gloves, protective sleeves.
Protective clothing--lab coats, aprons, Tyvek garments.
OSHA standards for personal protective equipment
supersede other OSHA standards.
Personal hygiene
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No smoking, eating, drinking or application of cosmetics is
permitted in areas where carcinogens are in use (or in any
lab area!). No mouth pipetting!
Wash hands and any exposed skin if potentially
contaminated--face, neck, forearms, etc.
No shorts or open toed shoes.
Remove lab coat or other potentially contaminated
protective clothing before leaving the work area. Lab
coats need to be cleaned regularly; special washing
instructions may be needed. Contaminated disposable
clothing should be treated as hazardous waste
Labeling of containers
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All containers of chemical carcinogens need to have a
warning label affixed to them. A Right-to-Know (RTK)
style label must be on any container of material that is
repackaged or made into a solution more than 0.1%.
All areas where carcinogens may be used, present or stored
should have prominently displayed warning signs or labels
both in the areas and access to them.. Some warning signs
and labels are described by specific standards.
“DANGER--Contains ___________
CANCER HAZARD”
Storage of containers
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Carcinogens must be stored separately from other
materials.
Separated by shelving system or secondary containment.
Secondary containment means placing chemical containers
in an outer container to prevent the release of a chemical in
the event that its container breaks or ruptures.
Desiccators, plastic boxes, bottle-in-can are acceptable
secondary containment.
Storage areas must be labeled “Danger--Carcinogens
Stored Here.”
Housekeeping and maintenance
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Keep all work surfaces and equipment clean.
Dry sweeping or compressed air cleaning of floors or work
surfaces is prohibited.
Dry cleaning of surfaces and equipment must be done by
vacuum systems with high-efficiency filters.
All contaminated floor sweepings, debris (paper towels,
Kimwipes, plasticware), discarded filters from respirators
or vacuums must be bagged, properly labeled and sent out
for incineration.
Regulated areas
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Establish regulated or designated areas for the use of
carcinogens. (Required in Lab Standard.)
Locations where entry and exit or use of an area is
restricted to the use of carcinogens.
Only authorized persons trained in the use of the
carcinogens present may use these areas when such
materials are in use.
Regulated areas are usually under negative pressure (fume
hood) to contain carcinogens in the hood or room.
Decontamination and emergency procedures
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Safety shower and eyewash station nearby.
Special solutions or solvents on hand if required for
decontamination of skin, eyes.
Spill mixtures and cleanup materials for spills on hand.
All used spill cleanup materials must be treated as
hazardous waste.
Respirator may be needed for spill cleanup.
Any “incidental” spill may be cleaned up by the lab staff;
larger spills may require a emergency response (5-1111).
Fire extinguisher at hand as required. Training needed.
Written emergency response plan. Training required.
Monitoring
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If there is reason to believe that a PEL may be exceeded
then personal exposure monitoring is required. This may
be done by EH&S staff. Personnel monitoring with sample
pumps or badges.
Area monitoring may be required in some cases.
Medical monitoring may be required if it is anticipated that
PELs may be exceeded. Examination by a physician,
blood tests, etc. Required whenever there is a spill or other
emergency.
Results of monitoring must be supplied to the employee.
Records of exposures,. monitoring, and medical exams
must be kept for 30 years.
Administrative controls
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Material Safety Data Sheets and other information.
Training--all employees using carcinogens must be trained
in the recognition of the physical and health hazards
associated with the carcinogens they are working with,
methods to detect the presence or release of a carcinogen
and ways to protect themselves from exposure to the
carcinogens with which they are working.
Specialized training may be required for specific
carcinogens.
Written exposure control plans, if required.
Limitations on the duration of exposure.
How do I dispose of waste carcinogens?
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With very few exceptions (dilute formaldehyde solutions)
carcinogens may never be discharged to the sanitary sewer.
Carcinogens may never be disposed of in the ordinary
trash.
Waste bottles must be properly labeled, tightly capped at
all times (except when adding or removing waste) and they
must have secondary containment. See section 7.9-11 of
the CHP for waste bottle labeling instructions. Check
“Poison” on the waste label.
Dry wastes must be incinerated or shipped out as regulated
medical waste (“chemotheraputic agents”).
How do I reduce my inventory and level of waste generation?
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Plan the use of carcinogens carefully. Do not make more
stock solutions than are required.
Substitute less hazardous materials for carcinogens
whenever possible; toluene instead of benzene.
Purchase carcinogens in the smallest possible quantities.
Do not allow inventories to accumulate. Place no longer
needed materials in a recycling program or dispose of as
waste.
Detoxify carcinogens as part of your research protocols.
Formaldehyde is easily detoxified by NH4OH, for
example.
The Standard Operating Procedure (SOP)
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Standard Operating Procedures (SOP) “relevant to safety
and health considerations” need to be developed when
carcinogens are in use. An SOP may be developed for an
individual carcinogen, a process or a class of chemicals.
An SOP must contain the following: The name and
location of the chemical, purchasing and usage authorization, training requirements, location of use, PPE required,
methods of waste disposal, decontamination, first aid
measures, spill control, emergency phone numbers and any
other relevant information.
Employees must be trained in the content of the SOP.
The End
“There are old researchers and there are bold
researchers, but there are no old, bold
researchers!”
Anon.