Department of Environmental Health
Division of Epidemiology and Biostatistics
University of Cincinnati
PO Box 670056
Cincinnati OH 45267-0056
Delivery Address
160 Panzeca Way
Cincinnati OH 45267
513-558-0045
October 30, 2015
Dear Senate Committee Members,
Thank you for the opportunity to discuss the study that my team conducted regarding
firefighters. My name is Dr. Grace LeMasters PhD., and I am Professor Emerita at the
University of Cincinnati, College of Medicine. I am an occupational and environmental
epidemiologist and former director of the Division of Epidemiology and Biostatistics. I have been
conducting research on occupational exposures and health effects for over 30 years. Besides
my research on firefighters (FF), I have conducted occupational studies with the military
examining the health effects of fuel and solvent exposures, with the refractory ceramic fiber
industry (replacement for asbestos) examining fiber inhalation and pulmonary disease and
cancer, with the food flavoring industry and pulmonary disease, and with carpenters related to
ergonomic hazards, to name a few. I have published over 200 peer-reviewed papers in scientific
journals and received the Silver Star from the Department of Defense for my work in preparation
for possible biologic warfare in the Middle East. I was on the committee of the International
Agency for Research on Cancer (IARC), that produced Monograph 98 regarding ‘Evaluation of
Carcinogenic Risks to Humans for Painting, Firefighting and Shift work”. Hence, I would
consider myself an expert in the area of occupational and environmental exposures and human
health effects.
The University of Cincinnati College of Medicine 2006 Study: I will start by briefly reporting on
how our study “Cancer Risk Among Firefighters: A Review and Meta-analysis of 32 Studies”
(LeMasters et al. JOEM. 2006;48:1189-1202) was initiated and the reasons for undertaking the
study. The Bureau of Worker’s Compensation (BWC) of Ohio funded the Occupational Medicine
Division to train residents and to do research in areas of their interest. One interest of the BWC
was cancer in FF. It should be noted that I was not paid to do this study and received only a
small sum ($10,000) to partially fund a graduate student. The study required over three years to
complete and publish. The reason for undertaking this study was because of my concern of the
numerous cancer causing agents that FF are exposed to and the seeming lack of awareness
among the scientific and firefighting community of the potential long term consequences of
these exposures.
We conducted a meta-analysis of approximately 100,000 firefighters from nine countries. A
“meta-analysis” is a powerful statistical tool that we used to summarize the data from 32 studies.
It is used when large sample sizes are needed for rare conditions such as cancer. Of the 20
cancers we investigated, 10 were found to be statistically significantly related to firefighting.
These included multiple myeloma, non-Hodgkin lymphoma, prostate, testicular, skin, malignant
melanoma, brain, rectum, stomach and colon. Some might wonder about why so many different
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types of cancer were associated with firefighting. I will address the issue of biological plausibility
that is most definitely related to the “chemical soup” for which firefighters (FF) have exposure.
Biologic Plausibility and the University of Cincinnati 2010 Exposure Study: The adverse effects
of smoke exposure can be traced back 225 years to an association between soot exposure and
a high incidence of scrotal cancer among chimney sweeps reported by Sir Percival Pott, a
London surgeon. ( Melicow MM (1775 Percival Pott (1713-1788): 200th anniversary of
occupation-induced cancer of scrotum in chimney sweeps. Urology 6:745-749) As a follow-up
to our 2006 study, Underwriters Laboratories in partnership with the Chicago Fire Department
and colleagues from my department at the University of Cincinnati (Baxter et al. 2010)
conducted a 16 month study on the hazards that smoke and gas exposure pose to firefighters.
The clothing of FF was contaminated with many metals including aluminum, calcium, iron,
magnesium, and zinc (in 10/11 fires); chromium, potassium, copper and arsenic (in 5/11 fires);
and strontium which exceeded NIOSH and OSHA recommended standards. The investigators
concluded that “Smoke exposures repeatedly exceeded ACGIH recommended exposure limits
and consisted of particulate in the submicron range (respirable and absorbable)”. Numerous
chemicals (n=26) were also measured and were found on the clothing of FF. FF are exposed to
chemicals called PAHs through incomplete combustion of organic materials, vehicle diesel
exhaust, and smoke derived deposits on the skin. Another study showed that FF are regularly
exposed to elevated levels of PAHs and a PAH metabolite was detected in the urine of FF
within 6-7 hours after a fire and more than 4 days after fire suppression despite the use of
protective equipment (Caux et al. 2002). Below is a partial list of a few of the cancer causing
agents that FF are routinely exposed to, the IARC carcinogen class level (1 means known
human carcinogen, 2A means probable and 2B means possible) and the possible source of
these exposures. I am sure you have heard of many of these chemicals.
Carcinogen (IARC class) Possible Source/Activity
Acetaldehyde (2B)
Residential fires, exhaust; Knockdown, overhaul,
Metals (Arsenic (1), Cadmium
(1), Inorganic Lead (2A)
Overhaul, fires in old buildings
Benzene (1)
Present in almost all fires with wood structures
1,3 Butadiene (1)
Mixed occupancy buildings, electronics, grasslands
Diesel exhaust (1)
Trucks started in/near firehouse and running at fires
Formaldehyde (1)
Burning textiles, particle board,
Vinyl Chloride (1)
Components of plastics, metals, insulation, and packing
Benxo(a)pyrene (1)
Formed during incomplete combustion of materials
Di-2ethylhexylphthlate (2B EPA-probable human carcinogen) Used in plastizers
Soot (1), Carbon Black (2B) All fires during incomplete combustion
How Exposures Can Occur: Exposures to chemical carcinogens can occur through absorption
by the lungs in a vapor state from inhaled particles, absorption through the skin (the largest
organ of the body) from smoke derived deposits on skin and clothing and by accidental
ingestion. During the process of fighting fires, inhalation exposures may occur due to leakage
or removal of the air supplied respirator when smoke is still in the air or during overhaul
operations. The rate of skin absorption to these chemicals is likely accelerated because of
prolonged exertion and increased body temperatures generated during firefighting. In a study of
coke oven workers (VanRooji et al. 1993), another hot environment, the skin was the main route
of uptake of certain chemicals. Exposures may occur to FF from wearing clothing that was
previously contaminated. Contaminated gear can act as a compress to the skin which adds
adsorption of chemicals. It is often hours before FF have an opportunity to remove their
contaminated gear and wash. Thus, at the fire scene, FF are exposed to complex mixtures of
agents which include respirable smoke particles, toxic gases and chemical agents that have
been classified as known or suspected cancer causing agents by IARC, the Occupational
Safety and Health Administration (OSHA), the National Institute for Occupational Safety and
Health (NIOSH) or the American Conference of Governmental Industrial Hygienists (ACGIH).
In summary, I would like to emphasize that FF work in a multiplex environment with a wide
range of exposures to toxic and cancer causing agents both at the fire scene and at fire stations
including metals, toxic gases, ultrafine particulates and organic compounds which may be
present in the vapor and/or particulate form. FF are routinely exposed to numerous chemicals
that have been associated with several types of cancers. I personally know of no other
occupations that have exposures to so many cancer causing agents on a routine basis. Thus,
because of the complex exposures to metals and chemicals that FF usually encounter it would
be expected that they would be subjected to several types of cancer.
Respectfully submitted,