Jackson to step down as Obama's environmental chief

WASHINGTON: U.S. Environmental Protection Agency chief Lisa Jackson, who spearheaded the Obama administration's crackdown on carbon emissions, said on Thursday she will step down after almost four years of battles with Republicans and industry over proposed regulations.

Under her leadership, the agency declared for the first time that carbon dioxide was a danger to human health and could be regulated under the Clean Air Act, leading the EPA to develop a new regulatory regime to limit carbon emissions.