Research links wildfire smoke with cardiac arrest in men

smoke prescribed fire firefighter

A firefighter is enveloped in smoke while working on a prescribed fire in Hot Springs, SD, March 30, 2013. Photo by Bill Gabbert.

Researchers in Australia have found a link between smoke from bushfires and cardiac arrest in men over 35 in the population of metropolitan Melbourne. We would like to see a study done of wildland firefighters who breathe far more smoke than the residents of Melbourne.

Below is an excerpt from

Men over 35 have an increased risk of cardiac arrest if exposed to poor quality air from bushfires, a new study has found.

Monash University research using data from Ambulance Victoria’s Victorian Ambulance Cardiac Arrest Registry (VACAR) investigated the links between out-of-hospital cardiac arrests and bushfire smoke exposure in metropolitan Melbourne during the 2006-07 bushfire season.

The study, published in the latest edition of Environmental Health Perspectives, found an association between exposure to forest fire smoke and an increase in the rate of out-of-hospital cardiac arrests.

Monash University researchers led by Dr Martine Dennekamp, Department of Epidemiology and Preventive Medicine, saw greater increases in the number of men over 35 years old experiencing cardiac arrests but did not see a significant association in women over 35.

Dr Dennekamp said exposure to smoke from forest fires was a significant health issue in many countries, and it was important to raise community awareness.

“The problem is likely to get worse in the future, as we can expect fires to become both more frequent and more severe,” Dr Dennekamp said.

The state and federal governments not only employ the most wildland firefighters in the United States, but they would also be the ones to fund research like this. One would think they would have a disincentive to discover environmental conditions on the job that adversely affect the health of their employees. Don’t ask the question if you don’t want to know the answer, right? Mitigating the hazard of smoke for firefighters on a wildfire would be extremely difficult. But the least these employers should do is determine exactly the nature and scope of the hazard, and support their employees, and former employees, who suffer from life threatening diseases caused by their jobs.

There have been some papers written and some research has been completed on wildfire smoke, but what is needed is a thorough long term study on wildland firefighters conducted by epidemiologists. Something we first called for in 2010.

A very well known and respected Hotshot Superintendent advised me to frequently complete a CA-1 accident form after breathing lots of smoke on a fire. If you don’t, perhaps 10, 20, or 30 years later it might be hard to convince your employer that one or more of the following conditions were caused by your job: leukemia, testicular cancer, lung cancer, brain cancer, bladder cancer, ureter cancer, colorectal cancer, and non-Hodgkins’s lymphoma. All of those are recognized by the British Columbia government as an occupational hazard for firefighters; they are called presumptive cancers. But the United States government does not.

Other articles on Wildfire Today tagged cancer and firefighter health.

Study finds firefighters more likely to get two types of cancer

According to a recently published study, firefighters in three major municipal fire departments were more likely to be diagnosed with lung cancer and leukemia than the general population.

Researchers examined the firefighting exposure and medical histories of 20,000 firefighters with over 1,300 cancer-related deaths and 2,600 cancer incidence cases in Chicago, Philadelphia, and San Francisco who were on duty between the years 1950 and 2009. This was one of the largest studies of its kind, and was the first to relate the time elapsed during fire runs to cancer risk.

Among eight types of cancers examined, they found slight, but statistically significant positive exposure–responses for lung cancer and leukemia risk. The researchers wrote:

These findings contribute to the evidence of a causal association between firefighting exposures and cancer.

The study did not address the health effects on wildland firefighters who, unlike structural firefighters, do not have access to an effective breathing apparatus to provide them clean air to inhale into their lungs. There could also be significant differences between the harmful effects of vegetation smoke and that produced by materials in structure fires.

Some wildland firefighters, especially those on hand crews, are routinely exposed to smoke-filled air for hours each day when assigned to a large fire, sometimes for 14 days. At other times they can be stationed in a smoky environment 24 hours a day for weeks at a time when inversions trap smoke. This frequently occurs in northwestern California, for example on the Six Rivers, Klamath, and Shasta-Trinity National Forests. In those cases even non-firefighters working in administrative positions at the Incident Base have been adversely affected by breathing contaminated air.

As we wrote in January, 2011:

There needs to be a concerted effort to conduct a similar study on wildland firefighters. It should be led by a physician/epidemiologist and should evaluate the long term health and occurrence of cancer and other diseases among wildland firefighters. There is a lot of grant money out there and it should be possible to get some of it pointed towards this overlooked niche of firefighting.

Other articles on Wildfire Today tagged cancer and firefighter health.

9/11 health care bill does not cover firefighters’ cancer

Remember the huge battles to get the bill passed to provide health care for the firefighters that were suffering from medical issues after working in the debris from the towers that fell during the 9/11 attacks? Most of us felt a huge relief when the “S. 1334: James Zadroga 9/11 Health and Compensation Act of 2009“ was finally passed. We wrote about it several times, with the latest being HERE.

It turns out that the bill, or at least the way the provisions are being interpreted, does not cover the treatment of cancer for the firefighters that worked on the debris pile. Cancer — you would think this would be close to the number one condition covered for the people that worked in that toxic environment.

John Howard, the World Trade Center Health Program administrator, said in a statement that cancer would not be covered because there is not adequate “published scientific and medical findings” that a causal link exists between September 11 exposures and the occurrence of cancer in responders and survivors. So if we wait, and study the link for another, what, 20 or 30 years we can prove it then?

This is a disgrace.

Jon Stewart of the Daily Show, in a piece named “I Thought We Already Took Care of This S@#t”, expresses his opinion on the issue. The clip has profanity, but it is bleeped out. has more details about this development.

Meanwhile, the Canadian government has a vastly different approach. For years the provinces of Alberta and Manitoba have had presumptive coverage for a list of conditions for firefighters. If they are diagnosed with one of the cancers on the list, it is considered an occupational disease and they may be eligible for workers compensation benefits. In fact, Alberta expanded their list in May to include prostate, breast, skin and multiple myeloma, bringing the total to 14 types covered under the Workers Compensation Board. Their government acknowledges that firefighters are at a greater risk of contracting cancer than the general public, and it can be difficult or impossible to prove that a particular case of cancer was caused by a specific incident or exposure, on or off the job.

The future of wildland fire smoke research

JFSP smoke research planThe Joint Fire Science Program (JFSP) has released their plan for wildland fire smoke research. The 58-page document outlines their priorities for funding smoke research through 2015.

Much of the emphasis appears to be directed at how to deal with the public’s perception and tolerance of smoke. Smoke is becoming an increasingly sensitive subject to the population due to larger wildfires burning for longer periods of time, concern about the effects of wildfire smoke on global warming, and prescribed fires continuing to be an important tool for land managers.

One aspect of wildfire smoke that Wildfire Today has written about frequently is the short and long term effects of smoke on the health of firefighters. On April 23, 2010 we covered the study that NIOSH and the U.S. Fire Administration are conducting about cancer among structural firefighters. We called out the land management agencies and the firefighting associations:

There needs to be a concerted effort to conduct a similar study on wildland firefighters. It should be led by a physician/epidemiologist and should evaluate the long term health and occurrence of cancer and other diseases among wildland firefighters. There is a lot of grant money out there and it should be possible to get some of it pointed towards this overlooked niche of firefighting.

Followups to that article are HERE and HERE.

The JFSP five-year plan does mention research on the effects of smoke on wildland firefighters, but at times it seems like an afterthought. For example, the objective for one of four research themes, “Smoke and Populations”, sometimes includes the “impact of smoke on populations” (page 26), and in other places it is described as “impact of smoke on populations and fire fighters” (page 21).

However, the plan does list some specific “Smoke Science Foci” that may benefit firefighters:

  • 2011: (SSP T3 -2): Epidemiological research/literature review to determine human health risk from high PM loadings.
  • 2011 (SSP T3-4): Fire fighter smoke health hazards: trends in health and exposure.
  • 2012 (SSP T3-5): Review of epidemiological research to determine human health risk from high PM, high ozone and high aromatic hydrocarbon loadings with a focus on synergisms between pollutants.

We hope that the “foci” turns into actual research.

NWCG’s position on firefighter-cancer study

Before we published the article on April 23 about the study that NIOSH is conducting on a possible link between structural firefighters and the occurrence of cancer, as part of our research we emailed Michelle Ryerson, the chair of the National Wildfire Coordinating Group’s Risk Management committee, formerly called the Safety and Health Working Team. We asked if the NWCG was aware of any similar studies that involved wildland firefighters. We also explained to her that we had talked with Travis Kubale, the NIOSH study’s primary project officer, who at the end of the conversation became interested in perhaps doing a cancer study on wildland firefighters. We passed along Mr. Kubale’s contact information to Ms. Ryerson, as well as others in the NWCG.

Today we received a response from Ms. Ryerson, which she called “an update from the NWCG Risk Management Committee perspective”:

  • NWCG was never approached by NIOSH to be included in this study.
  • The NWCG is coordinating with US Fire Administration on potential of including wildland fire to the NIOSH study.
  • NWCG has an active Smoke Exposure Task Group (SETG) under the auspices of RMC who’s focus is smoke hazard identification and mitigation for wildland firefighters and support personnel in fire camp environments (SETG website should be up and working by end of May).
  • The SETG began smoke exposure monitoring in 2009 and will continue monitoring in 2010 so that we can better understand the levels of smoke exposure both in fire camp and fireline operations.
  • The SETG is also preparing a long-term project proposal abstract to seek study sponsorship from universities, NIOSH, and other scientifical organizations.
  • Also worth mentioning is the fact that the DOI, FS, and many state agencies have instituted wildland firefighter medical standards programs that help track firefighter health issues throughout their arduous duty fire career.

We replied to Ms. Ryerson and the others that she had cc’d with her response:

I can imagine that employers of wildland firefighters may not be enthusiastic about opening a can of worms that may link cancer with exposure to smoke on wildland fires, but the Right Thing To Do is to look at this issue and either prove or disprove a link. I hope the NWCG will not only continue to collect data about the fire environment, but will also pursue a possible cancer link with just as much enthusiasm.

Follow-up on cancer risk among wildland firefighters

(Revised @ 2:50 MT, April 26, 2010)

More information has come to light regarding the article we wrote last week about “Cancer risk and smoke exposure among wildland firefighters“. In response to an email, we heard from Brian Sharkey of the USFS’ Missoula Technology and Development Center, an exercise physiologist who was instrumental in the design of the Step Test and Work Capacity Test for wildland firefighters. We asked Mr. Sharkey if he was aware of any studies that considered a possible increased cancer risk for wildland firefighters. He said no, and:

However, our 1997 risk assessment (Booze in Health Hazards of Smoke, 1997) showed an increased risk only when we used “worst case scenario” – which estimated career exposure at exposure levels 95% of highest values measured. No one works for 25 years anywhere near those values. Also, some carcinogens are not as high on fires as they are in winter (from burning wood in stoves) (Smith et al.).

Structural FF do not have increased risk of lung cancer. Chinese women who cook over coal fires have more cancer – those who cook over wood fires do not.

We need a study of health effects that looks at all causes of morbidity and mortality – not just cancer (where risk is about 1 in 3 for US population). We also need an injury/illness surveillance system that tells us the impact of fire on respiratory, cardiovascular and – yes – cancer.

We asked Mr. Sharkey what data supported his statement that “structural FF do not have an increased risk of lung cancer”, and he was in a hurry, about to leave for a “smoke meeting”, but referred to a study on Philadelphia firefighters. We found the 24-year old study to which Mr. Sharkey may be referring. Here is an excerpt, the Methods, Results, and Conclusions:

We conducted a retrospective cohort mortality study among 7,789 Philadelphia firefighters employed between 1925 and 1986. For each cause of death, the standardized mortality ratios (SMRs) and 95% confidence intervals were estimated. We also compared mortality among groups of firefighters defined by the estimated number of career runs and potential for diesel exposure.

In comparison with U.S. white men, the firefighters had similar mortality from all causes of death combined (SMR = 0.96) and all cancers (SMR = 1.10). There were statistically significant deficits of deaths from nervous system diseases (SMR = 0.47), cerebrovascular diseases (SMR = 0.83), respiratory diseases (SMR = 0.67), genitourinary diseases (SMR = 0.54), all accidents (SMR = 0.72), and suicide (SMR = 0.66). Statistically significant excess risks were observed for colon cancer (SMR = 1.51) and ischemic heart disease (SMR = 1.09). The risks of mortality from colon cancer (SMR = 1.68), kidney cancer (SMR = 2.20), non-Hodgkin’s lymphoma (SMR = 1.72), multiple myeloma (SMR = 2.31), and benign neoplasms (SMR = 2.54) were increased among firefighters with at least 20 years of service.

Our study found no significant increase in overall mortality among Philadelphia firefighters. However, we observed increased mortality for cancers of the colon and kidney, non-Hodgkin’s lymphoma and multiple myeloma. There was insufficient follow-up since the introduction of diesel equipment to adequately assess risk. Am. J. Ind. Med. 39:463-476, 2001. Published 2001 Wiley-Liss, Inc.

Wildfire Today has called for a study on the cancer risks associated with wildland fire. Not just lung cancer. The study needs to be conducted by medical doctors and epidemiologists.

We also learned that a proposal was prepared by Joseph Domitrovich in December, 2008, for the US Forest Service Technology and Development Program to study the effects that carbon monoxide may have on the cognitive function of wildland firefighters. Here is an excerpt.

An extensive EPA review on CO effects (2000) concluded that behavioral impairments in healthy adults are not significant below 20% carboxy hemoglobin (COHb). However, some studies have showed mild impairments at 5% COHb or below. Cigarette smokers have COHb levels of 5-10%, sometimes as high as 15%. In view of the reported adverse effects among fire staff, suspect additive or synergistic interactions among pollutants that worsen the neurobehavioral effects that would be predicted from CO exposure alone.

The deliverable outcome of the proposed project is a report detailing the levels of smoke exposure and cognitive effects. This could then be used by IMT, crew bosses along with training (RX-410) to help better understand the potential cognitive effects when exposed to wildland fire smoke.

This project will help us to better understand the effects of wildfire smoke on our cognition, which would increase safety of fire personal.

Wildfire Today recommends that this study be funded.

A “smoke meeting” is being held in Boise this week. It will interesting to see if anything that will benefit the health of firefighters will come out of the meeting. We understand that at least one actual medical doctor is beginning to be involved in smoke studies related to wildland firefighters, which is a step in the right direction.

More information about wildland firefighters and smoke. It begins on page 8 (page 74 of the main publication).