COPENHAGEN (AP) - The head of the U.S. Environmental Protection Agency says she will take commonsense steps to regulate carbon emissions to protect the health of Americans.

EPA Administrator Lisa Jackson said her newly declared power to regulate greenhouse gases will be used to complement legislation pending in Congress, not replace it.

She said "this is not an either-or moment. It's a both-and moment."

EPA declared Monday that carbon emission could endanger human health and would be subject to federal regulation.

Jackson spoke Wednesday at the 192-nation climate conference in Copenhagen, which is trying to forge an international treaty to control the gases causing the Earth's temperature to rise.