Pity firefighters. Battling a blaze in protective clothing and self-contained breathing apparatus (SCBA) is a trade-off between personal protection and thermal strain. Summer heat increases the dangers. Data shows that heart attack due to heat stress is the number one cause of death in firefighters.

Researchers Tom McLellan, PhD, and Glen Selkirk, MSc, set out to reduce some of the risks. Their study, "The Management of Heat Stress for the Firefighter," defines safe work limits for individuals wearing protective clothing and SCBA, and explores strategies to reduce the thermal burden. Working with Toronto Firefighters in ambient summer conditions, the researchers compared active and passive cooling strategies in combination with different levels of hydration. They found that the active approach -- a combination of fluid replacement and misters or the submersion of the forearm and hand in cool water -- effectively brings down the body's core temperature. The study found that this combination was twice as effective as the passive approach -- hydration and the removal of the protective clothing only.

Their report suggests specific strategies for minimizing the risk, and presents a slide rule for commanders to determine safe work limits for firefighters during activities involving full gear.

The pocket guide, a 96-page resource for managers and health and safety professionals published by the Canadian Centre for Occupational Health and Safety (CCOHS), uses roofing and foundry work as examples of extremes. "Working in Hot Environments: A Health and Safety Guide" explains the risks of heat exposure, and points out that it can be controlled. It guides readers through health and safety law related to heat stress, emphasizing the importance of developing and implementing safe work practices to prevent or minimize exposure.

The guide advises on occupational exposure limits and thermal comfort guidelines, and explains how heat exposure is measured. It offers instructions on using engineering and administrative controls to maintain a comfortable and safe temperature in the workplace, and recommends personal protective equipment and safe work practices. A section on heat-related illnesses explains the seriousness of these potentially fatal conditions, listing the symptoms and what to do when they are detected.

The publication, "New Heat Stress Calculator Tool for Firefighters: Putting Research into Action, published by the Municipal Health and Safety Association in Toronto," puts the McLellan-Selkirk findings to work.

All three publications make an important contribution to the understanding and prevention of heat stress in any context.

Sources: "New Heat Stress Calculator Tool for Firefighters: Putting Research into Action" -- Municipal Health and Safety Association (Toronto); "Working in Hot Environments: A Health and Safety Guide" - Canadian Centre for Occupational Health and Safety