What are leaking underground storage tanks and how are they being cleaned up?

FILE - Workers remove a 40,000-liter underground gasoline storage tank to be replaced with a new tank at a gas station in Sacramento, Calif., May 23, 2003.

For more than a decade, some residents of the tiny Richmond, Rhode Island, neighborhood of Canob Park drank and bathed using tap water that had been tainted by gasoline that leaked from storage tanks buried under service stations a few hundred yards from their homes. They spent years battling oil companies, dealing with the daily misery of boiling most of their water and wondering about lasting damage to themselves and their children.