The Bush administration's proposal is awaited by the head of the Senate Environment Committee, Vermont Independent Jim Jeffords, who has pledged to push ahead with legislation requiring drastic cuts of at least 75 percent in four pollutants spewed by U.S. utilities.

The senators said they "are concerned about rumored changes to the NSR program that might undermine its benefits," said a letter dated Dec. 14 to EPA Administrator Christine Todd Whitman.

The letter was signed by Democrats Bob Graham of Florida, Jeffords, Hillary Rodham Clinton of New York, Thomas Carper of Delaware, Ron Wyden of Oregon and Jon Corzine of New Jersey.

"We therefore are requesting that EPA immediately preserve and docket for the (committee) all documents" on EPA's NSR rulemaking, its consultations with Energy Secretary Spencer Abraham, and pending enforcement actions.

At a House Energy and Commerce subcommitee hearing on Wednesday, California Democratic Rep. Henry Waxman asked Energy Department Deputy Secretary Francis Blake to submit a roster of industry executives and environmental groups he has met with on the NSR issue.

Democratic lawmakers want to require U.S. utilities to begin making steep cuts in 2002 emissions of sulfur dioxide, nitrogen oxide, mercury and carbon dioxide.