BYU researchers hope to fine-tune wildfire behavior models

BYU fire research
Professor Thomas Fletcher and his students study fire behavior at BYU.

A chemical Engineering professor at Brigham Young University said the fire behavior model currently being used to predict the spread of wildfires “doesn’t have a lot of physics in it” and “it’s not as good as it could be”. Wildland firefighters have been using the Behave and BehavePlus fire modeling systems for decades.

Using grants from the U.S. Forest Service and the National Science Foundation, Thomas Fletcher expects to add several components to the existing models.

Here are some excerpts from an article on the BYU web site:

Most recently, Fletcher published an article in the International Journal of Wildland Fire detailing how a leaf can burn even with up to 50 percent of its moisture present. This previously unknown fact has serious ramifications for existing models, which often mistakenly factor in the additional time it takes for a leaf’s moisture to evaporate.

“Once a fire gets going, it doesn’t matter if you have wet leaves or bone-dry plants,” Fletcher said. “A big enough fire can ignite the leaves even though there still may be some moisture in the vegetation.”

Over the years, Fletcher and his team have focused on improving three aspects of fire models: the impact of moisture on fires, how wind affects flame and how flame spreads through shrubs.

“The model the fire boss usually runs on his laptop doesn’t have a lot of physics in it,” Fletcher said. “It runs fast and predicts something, but it’s not as good as it can be. We’re trying to improve that model so he can better understand where the fire is, where it’s going, which houses can be saved and where he can safely place firefighters.”

David Weise, supervisory research forester at the USDA Forest Service lab in Riverside, Calif., said Fletcher’s team complements others across the country working to improve the fire models.

“Tom’s fundamental work is providing us with information that can be used in our next generation of models,” Weise said. “The live fuels he’s working on are something we’ve found is important for us to look at, because our current models are dominated by dead fuels.”

Three articles written by Fletcher have been published in the International Journal of Wildland Fire, an official publication of the International Association of Wildland Fire.

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:

Methods
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.

Results
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.

Conclusions
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.

PROPOSED TECHNOLOGY & DEVELOPMENT WORK:
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.

POTENTIAL BENEFITS:
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.

Cancer risk and smoke exposure among wildland firefighters

(Note: after we wrote this article, more information came to light, and we wrote a follow-up piece.)

NIOSH and the U.S. Fire Administration are conducting a study of cancer among firefighters. I talked with the physician/epidemiologist, Dr. Tom Hales, who is a co-investigator for the study which began in October, 2009 led by Travis Kubale, the study’s primary project officer. He said that over the next four years they will study firefighters from three fire departments: San Francisco, Chicago, and the District of Columbia. They will look at the causes of death of firefighters that have worked for the departments over the last 50 years and compare that with tumor registries in their local communities and the National Death Index for cause of death.

Dr. Hales said that they will ask the firefighters in the study if they have ever worked on wildland fires, but other than that, they will not collect data on firefighters who specialize in wildland fires. He also said that NIOSH has no plans to specifically study cancer rates among wildland firefighters, but emphasized that NIOSH has collected data on smoke exposure on active wildfires and prescribed fires (see below).

What about wildland firefighters?

It is unfortunate that wildland firefighters will not be evaluated in this study, but you have to consider that the probably-flawed TriData study only looked at structural firefighters, and the IAFF and IAFC who helped to push for this new study spend most of their energy and political capital on structural fire.

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.

Wildfire Today is calling out the following organizations to get together and put some pressure on FEMA, NIOSH, and the U.S. Fire Administration to get this done:

  • National Park Service
  • Bureau of Land Management
  • U.S. Fish and Wildlife Service
  • Bureau of Indian Affairs
  • U. S. Forest Service
  • National Wildfire Coordinating Group and their Risk Mgt. Comm.
  • State land management agencies
  • International Association of Wildland Fire
  • International Association of Fire Chiefs
  • International Association of Fire Fighters
  • Federal Wildland Fire Service Association

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Below are links to studies about smoke exposure on wildfires, as well as excerpts from a bibliography on the same subject.

Continue reading “Cancer risk and smoke exposure among wildland firefighters”

FEMA awards grant to study whole-house fire shelter

In May, 2008, Wildfire Today wrote about two patents that were issued in the 1990’s for systems to deploy fire shelters, or fire-resistant blankets, to cover entire houses. These may or may not be feasible, but now the Federal Emergency Management Agency has awarded a $1 million grant to research the best material for whole-house fire-resistant blankets.

More information is here.

Thanks Dick