Firefighters' Risk for Heart Disease Increased by Ultrafine Air Particles

A new study has found that more than 70% of particulates released during fires are ultrafine, invisible to the naked eye, placing firefighters at an increased risk for heart disease from exposure during the fire suppression process.

Researchers at the University of Cincinnati (UC; OH, USA), Underwriters Laboratories (UL; Camas, WA, USA), and the Chicago Fire Department (IL, USA) conducted a series of simulated house and automobile fires to measure the amount and specific characteristics of breathable particulates released during combustion and, consequently, what firefighters are exposed to during the course of their typical work environment.

Fire suppression takes place in two phases. In the first, known as "knockdown," firefighters squelch the flames with water to avoid fire spread. Workers are required to wear protective breathing equipment during this time to avoid exposure to smoke and toxic gases produced from the process. During "overhaul," the second phase, firefighters enter the structure and work to prevent re-ignition of partially burned material. The researchers found that levels of ultrafine particulates were highest during overhaul, both in indoor and outdoor structure fires, as well as in automobile fires. The study was published in the August 2010 issue of the Journal of Occupational and Environmental Medicine.

"Firefighters simply can't avoid inhaling these ultrafine particles when they are not wearing their protective breathing apparatus and, unfortunately, they routinely remove it during overhaul,” said coauthor Stuart Baxter, Ph.D., a UC professor of environmental health. "Standard issue firefighting equipment weighs about 60 pounds [27 kg], and under the exertion of firefighting the standard air tank only lasts about 20 minutes, so as soon as they determine the situation is safe, typically during overhaul, firefighters shed the protective gear.”

Coronary heart disease (CHD) is the No. 1 killer of American firefighters, with many of these incidents taking place during or just after a firefighting incident. The researchers claim exposure to harmful ultrafine air particulates could predispose firefighters to CHD, particularly in those at a less-than-optimal level of physical fitness or personal health.

Related Links:
University of Cincinnati
Underwriters Laboratories
Chicago Fire Department