The US Air Force (USAF) and US Navy (USN) are switching to safer aircraft firefighting foam, after tests showed that chemicals used for decades by military firefighters contain carcinogens, which have contaminated drinking water on and near military installations.
The use of foam containing toxic chemicals has spawned numerous civil lawsuits over drinking water contamination, as concern has also been raised about firefighter exposure to the chemicals. But the problem can be limited to a degree through the use of a system developed to eliminate pollution during mandatory testing of aircraft rescue and firefighting (ARFF) vehicles.
Aqueous film-forming foam (AFFF) is used primarily by firefighters to extinguish Class B (flammable liquid) fuel fires. It contains perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS).
In 2002, 3M, the primary manufacturer of AFFF with PFOS, voluntarily phased it out of production in the United States. Even so, much legacy AFFF with PFOS remains. One study in 2011 calculated that about 10,000 tonnes of PFOS-based firefighting foam was still in stock or in service in the United States. Estimates for the Asia-Pacific region are that 30-40 percent of all foam stocks are still PFOS-based. In 2006, eight major companies voluntarily agreed to phase out their global production of PFOA, although there are a limited number of ongoing uses for it.
PFOA and PFOS were used in decades past to make carpets, fabric, microwave popcorn bags, fast-food wrappers, and 'non-stick' fry pans resistant to water, grease, or stains.
While consumer products and food are a large source of exposure to these chemicals for most people, drinking water can be an additional source in the small percentage of communities where these chemicals have contaminated water supplies. Such contamination can occur near military airfields, where they were used in the aftermath of an aircraft crash or for firefighter training.
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