Hilcorp Energy Co., Exxon Mobil Corp., Conoco COP -5.27%▼Phillips and Occidental Petroleum Corp. OXY -3.40%▼ are the U.S. oil-and-gas industry’s top emitters of planet-warming greenhouse gases, according to a new report based on federal data.
The four companies are also the top emitters of methane, according to the report Thursday by environmental nonprofits Ceres and the Clean Air Task Force. Methane has been of increasing concern to environmentalists because it traps roughly 85 times more heat than carbon dioxide.
