Health Beat–October, 2002–The “Smoldering” and “Flying” Hazards, Part 1

Mary Jane Dittmar
Senior Associate Editor
Fire Engineering

The next time you are tempted to take off your respiratory protection during overhaul operations for reasons of comfort, consider the following.

“The most dangerous time for firefighters is after the fire is out,” according to an in-depth study conducted by Robin Rowland, CBC News in Canada. “Smoke, fumes and soot are still present at the site.” The report “Deadly Duty, Firefighters Cancer Risk,” says that at least 15 studies show a statistical link between brain cancer and firefighting.

Epidemiologist Kristin Aronson, a specialist in the causes of cancer quoted in the report, fingers toxins created by smoldering plastics as the primary suspect after having analyzed death reports of 6,000 Toronto firefighters. Potentially cancer-causing vapors found in smoke, she adds, come from “glues, wraps, paints, insulation, and other building materials-the synthetics found in almost every article of modern day life.” Polyvinyl chloride (PVC) is found in upholstery, wire, pipes, and wall coverings. When burning, PVC gives out hydrogen chloride and phosgene. Actually, polyethylene and PVC can be more dangerous when smoldering than when burning at the height of the fire. They emit carbon monoxide, hydrogen cyanide, hydrochloric acid, and other hazardous chemicals.

One fact that may be indicative of the plastics-brain cancer link is that earlier studies of firefighter mortality (those done before the widespread introduction of plastics in the 1950s) did not identify brain cancer as a cause of death.

Brain cancer in firefighters with 20 years of experience is so common in Ontario that it is recognized as a workplace injury and victims are automatically compensated. (Ontario is the only Canadian province that does this.)

A 1994 Ontario Industrial Disease Standards Panel report estimated that “80 percent of firefighters’ injuries are caused by smoke inhalation or oxygen deficiency and that more than 50 percent of line-of-duty deaths are caused by smoke exposures.” The report noted also that firefighters sometimes found the breathing apparatus too hot, heavy, and cumbersome under strenuous conditions and found it difficult to breathe once the tank had reached 30 percent capacity. They, therefore, often removed their breathing apparatus as soon as they perceived that the fire was no longer a danger to them, exposing themselves to the dangerous chemicals in the smoke-each substance dangerous in itself and most likely even more so (the extent of the danger is unknown) when mixed and heated with other agents in the fire environment.

In relation to carbon monoxide, considered by some as possibly the most hazardous chemical for firefighters, it was found that firefighters who take their breathing apparatus on and off in the fire environment are virtually at the same risk as those who do not wear the apparatus at all. Since carbon monoxide is odorless, colorless, and tasteless, you cannot determine how much is in the air you are breathing without using a detector. Some experts say the amount of smoke present is not necessarily indicative of the quantity of carbon monoxide present.

The 1994 Ontario study has shown that firefighters outside Ontario are just as likely to get brain cancer, which means that–since all the suspected materials and substances are in use throughout the United States and virtually the world–all firefighters should be aware of these risks and protect themselves to the maximum.

Next time, some additional commonly found hazards.


  1. 1. Investigative Report: Firefighters Cancer Risk, David Mc Lauchlin and Curt Petrovich, CBC Radio News; Dr. Brian Goldman, CBC Television News; Robin Rowland & Gary Graves, CBC News Online,, Feb. 5-6, 2001

  2. “Firefighters face cancer risks”, Feb. 6, 2001.

No posts to display