U.S. documents released under the Freedom of Information Act reveal that lax safety standards at Kadena Air Base in Okinawa may be to blame for the recent contamination of local drinking water sources.

The internal reports expose a spate of accidents at the base during the past 15 years that have involved at least 21,000 liters of fire extinguishing agents — some of them toxic.

In one incident last May, described by base officials as "vandalism," a drunk U.S. Marine activated a firefighting system. It filled a hangar with more than 1,500 liters of JET-X 2.75 percent — a foam classified by the U.S. government as hazardous. It contains chemicals known to cause cancer, and neurological and reproductive disorders.