Environmental Protection Agency Administrator Lisa Jackson is defending the rigor of the agency’s study of potential water contamination linked to the controversial natural-gas drilling method hydraulic fracturing.

From her testimony about EPA’s proposed budget to be delivered to a congressional panel Tuesday:

As I’ve mentioned before, natural gas is an important resource which is abundant in the United States, but we must make sure that the ways we extract it do not risk the safety of public water supplies. This budget continues EPA’s ongoing congressionally directed hydraulic fracturing study, which we have taken great steps to ensure is independent, peer reviewed and based on strong and scientifically defensible data.