Firefighting foam that flowed freely from an aircraft hangar on Friday has been classified as a hazardous materials incident by the Manassas Fire Rescue Department in northern Virginia.
Responders answering an automatic alarm at Manassas Regional Airport found a hangar overflowing with high-expansion fire-retardant foam spilling from an accidently activated fire suppression system, also known as a deluge system.
The foam had crossed nearby Wakeman Drive, forcing firefighter to detour traffic, the fire department’s Facebook page reports.
Aqueous film-forming foam, which is known as AFFF, is a firefighting foam widely used in the aviation industry because it quickly extinguishes fuel fires by spreading across the surface, depriving the fire of oxygen. Research shows that firefighting foam containing fluorine chemicals known as per- and polyfluoroalkyl substances (PFAS) are persistent in the environment and may have adverse health effects.
Only AFFF, which contains these chemicals, has been proven capable of putting out fuel fires.
Any hangar with an aircraft access door over 28 feet in height, a single fire area greater than 40,000 square feet or able to house an aircraft with a tail height of more than 28 feet is required to have either a foam-and-water deluge system or a combination of an automatic sprinkler system and a low-level high expansion foam system.
Local media reports that the tenant renting the hanger called in a clean-up company with tankers to vacuum up the foam. The hangar involved is the only one at the Manassas airport equipped with the deluge-type fire suppression system.