Companies Fight to Keep Global Warming Data Secret

Some of the country's largest emitters of heat-trapping gases, including businesses that publicly support efforts to curb global warming, don't want the public knowing exactly how much they pollute.

Oil producers and refiners, along with manufacturers of steel, aluminum and even home appliances, are fighting a proposal by the Environmental Protection Agency that would make the amount of greenhouse gas emissions that companies release — and the underlying data businesses use to calculate the amounts — available online.