NIOSH: What do plastic, polyester, and foam have in common? They are synthetic materials found throughout most modern homes in everything from toys to furniture to appliances. Unlike wood, cotton, and other natural materials, synthetic materials are made in laboratories through chemical processes.
During a fire, these chemicals can burn hotter and faster, and produce more toxic smoke than natural materials. Evidence suggests that work-related exposure to these toxicants among firefighters corresponds to an increased risk of acute cardiovascular events and cancer.
To understand the risk of exposure from residential firefighting, NIOSH investigators and university and industry partners measured hazardous air emissions during different stages of firefighting. The investigators set 12 separate fires in safe and controlled settings to simulate residential firefighting conditions. This included furnishing the structures with modern fixtures. Six of the fires involved firefighters entering through the front door of the building to extinguish the fire. The others involved firefighters first dousing the fire through a bedroom window before entering through the front door.
Investigators then collected air samples for several chemicals, including benzene and other volatile organic compounds, poly-cyclic aromatic hydrocarbons, and hydrogen cyanide. For comparison, they tested air from three areas: 1) inside the structure during active fire; 2) inside the structure after fire suppression, also known as overhaul, when firefighters search for and extinguish any smoldering items; and 3) outside the structure near exterior crew-members like the incident commander. In addition, they took personal air measurements associated with job types in all three areas: fire attack, victim search, overhaul, outside ventilation (help vent smoke from structure), and command/pump operator tasks.
In general, median personal air measurements collected from interior crew-members were substantially higher than the recommended exposure limits for short-term exposure for the chemicals measured. Significant differences occurred by job type, with search and attack exhibiting the highest levels of chemical exposure. The maximum levels recorded for hydrogen cyanide for firefighters assigned to attack, search, and outside ventilation were higher than levels considered immediately dangerous to life and health. Outside ventilation crews may not always wear respiratory protection and as a result could breathe in the chemicals that were measured. Even though search and attack firefighters wear self-contained breathing apparatus to protect their lungs, exposure could also occur via the skin, either through direct contact or when removing contaminated gear after the fire.
Area air measurements also showed that the median amount of several chemicals tested was higher than recommended short-term exposure limits. Even in the area outside the burning structure, where workers like the incident commander typically do not wear respiratory protection, area air measurements downwind of the fire were higher than naturally occurring levels. These results highlight the importance of wearing self-contained breathing apparatus, even when firefighters are assigned to post-fire suppression jobs or exterior operations. They also show the need for establishing command centers upwind of a fire or, if that is impossible, wearing self-contained breathing apparatus for protection against airborne chemicals, according to the study published in the Journal of Occupational and Environmental Hygiene.
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