WASHINGTON - The U.S. Environmental Protection Agency has sent its final proposal on whether carbon dioxide and other greenhouse gas emissions pose a danger to human health and welfare to the White House for review, EPA Administrator Lisa Jackson told Reuters on Monday.

The EPA's final finding, if it follows the agency's earlier assessment and is approved by the Office of Management and Budget, would allow the EPA to issue rules later to regulate greenhouse gas emissions, even if Congress fails to pass legislation to cut U.S. emissions of the heat-trapping gases that contribute to global warming.

We sent the final proposal over to OMB on Friday, Jackson said in an interview at her EPA headquarters' office.

She said the OMB has up to 90 days to review the proposal, but the EPA would like a quicker timetable.

We've briefed them a couple of times. So we're hoping for an expedited review, Jackson said.

Along with its final endangerment finding, the EPA also sent to OMB the agency's final finding on whether cars and trucks cause or contribute to that pollution, Jackson said.

Such a finding would allow the federal government to regulate tailpipe emissions by increasing vehicle mileage requirement.

Jackson said the government is facing a hard deadline of next March to let automakers know of any required increases in fuel economy standards that would affect vehicles built for the 2012 model year.

She said the EPA received more than 300,000 comments on its initial proposed public health endangerment and vehicle pollution findings that were issued last April.

(Reporting by Tom Doggett; Editing by Marguerita Choy and Lisa Shumaker)