The head of the U.S. Environmental Protection Agency on Wednesday defended its regulations of power plants and other suspected pollutants amid Republican lawmakers’ charges that the EPA has exceeded its statutory authority and is bringing down the U.S. economy.

The agency work is “ensuring that all people have clean air to breathe, clean water to drink and that we remain globally competitive,” EPA Administrator Michael Regan told the House Committee on Oversight and Accountability. “Our partnership and our open and transparent dialogue with Congress is key to ensuring that my agency can carry its mission of protecting public health and the environment.”