Will the boom in natural gas drilling contaminate America's water supply?

In the debate over energy resources, natural gas is often considered a "lesser-of-evils." While it does release some greenhouse gases, natural gas burns cleaner than coal and oil and is in plentiful supply - parts of the U.S. sit above some of the largest natural gas reserves on Earth, but a new boom in natural gas drilling, a process called "fracking," raises concerns about health and environmental risks.

NOW talks with filmmaker Josh Fox about Gasland , his Sundance Award-winning documentary on the surprising consequences of natural gas drilling. Fox's film - inspired when the gas company came to his hometown - alleges chronic illness, animal-killing toxic waste, disastrous explosions and regulatory missteps.