When people think about the dangers that firefighters face, they naturally consider things like smoke inhalation, burns, and harm from collapsing buildings.
There are other, more hidden dangers to firefighters that can lead to long and short-term hearing loss. Ongoing research can help us figure out changes to equipment and their environments to help prevent this problem.
Exposure to several types of chemicals, such as heavy metals including lead and cadmium, can lead to hearing loss. This exposure can occur through the skin or by breathing, putting people fighting fires at risk when they’re in buildings containing these chemicals. Once these chemicals make it into the bloodstream, they travel to and get absorbed in the hearing nerve. This, in turn, can lead to hearing loss due to nerve damage. Exposure can also affect the small hairs, or cilia, in the inner ear. These hairs help sound travel through the ear, and they do not regenerate once they are dead. Once enough of these hairs are gone, the result is often long-term hearing loss. Urban firefighters are at particular risk for chemical exposure, in part due to the sheer number of fires they fight in buildings that are older and contain these dangerous chemicals.
Scientists have long recognized that short and long-term exposure to loud noises can lead to hearing loss. Prolonged exposure to sounds at 85 decibels or higher can lead to hearing problems, and shorter bursts at higher levels can lead to similar damage. These noises damage the inner ear structure, and they affect people of all ages. Firefighters are exposed to loud sirens, ventilation tools, saws, alarms, and other equipment that have operating sounds at dangerous levels, in some cases over 100 decibels. In cities, firefighters rarely have much room to move around to get themselves away from blaring sirens and alarms, and also have to put up with the normal loud noises of a busy urban setting.
The Combination of Factors
Exposure to both loud noise and chemicals can have a cumulative effect on the hearing of firefighters. This is true even if both exposures at are recommended levels, to the extent that the combination can cause more damage than excessive levels of just chemicals or noise. Because they have a negative effect on hearing in different ways, the combination of the two makes a bad problem worse. Many firefighters also work long shifts, such as 24 hours on and 48 hours off, meaning that they get prolonged exposure to these dangers.
Past research has made clear the links between noise, chemical exposure, and hearing loss. Scientists are continuing that work in the hopes of protecting firefighters against these dangers better. For example, researchers at Wayne State University are studying the hazards of lead and cadmium to firefighters in Detroit. Cadmium was used to protect metal in the auto industry, and many of the old building in the city contain lead paint. Studying this group of high-risk firefighters will hopefully give us additional insight into how to protect those who protect us.