Pearl Harbor Naval Complex, Hawaii
The site of the Japanese attack on Pearl Harbor in 1941 remains an ominous place even today, but for reasons that go beyond the shadow of war. In the years following the attack, intense and toxic industrial activity rose sharply. It wasn't until the 1980s that at least 30 hazardous waste sources were identified within the grounds of the complex.
Even worse, the waste was suspected to have leaked into Oahu's precious groundwater wells, which are the water source for more than 100,000 residents in the Honolulu area. The site also neighbors a national wildlife refuge. Cleanup efforts continue today.