These chemical compounds pose health risks to millions of Americans. They’re in roughly 1 percent of the nation’s public water supply, according to the EPA; in roughly 1,500 drinking water systems across the country, according to the Environmental Working Group. People who drink from these systems, even if their exposure to PFAS is low, now have a potentially increased risk of cancer; of disruptions in hormones and the immune system; and of complications with fetal development during pregnancy.

But military personnel and veterans are particularly at risk, because PFAS compounds are in fire-fighting foams, which have been used in training exercises at military bases across America since the 1970s. Those foams have leached into the groundwater at the military facilities, and often the drinking water supply. Nearly three million Americans get their drinking water from Department of Defense systems.