The White House in December refused to accept the Environmental Protection Agency's conclusion that greenhouse gases are pollutants that must be controlled, telling agency officials that an e-mail message containing the document would not be opened, senior E.P.A. officials said last week. The document, which ended up in e-mail limbo, without official status, was the E.P.A.'s answer to a 2007 Supreme Court ruling that required it to determine whether greenhouse gases represent a danger to health or the environment. This week, more than six months later, the E.P.A. is set to respond to that order by releasing a watered-down version of the original proposal that offers no conclusion. Instead, the document reviews the legal and economic issues presented by declaring greenhouse gases a pollutant. Over the past five days, the officials said, the White House successfully put pressure on the E.P.A. to eliminate large sections of the original analysis that supported regulation, including a finding that tough regulation of motor vehicle emissions could produce $500 billion to $2 trillion in economic benefits over the next 32 years. The officials spoke on condition of anonymity because they were not authorized to discuss the matter. Both documents, as prepared by the E.P.A., showed that the Clean Air Act can work for certain sectors of the economy, to reduce greenhouse gases," one of the senior E.P.A. officials said. "That's not what the administration wants to show. They want to show that the Clean Air Act can't work."