With the support of more than one-third of their House colleagues, a bipartisan congressional group yesterday unveiled new legislation to control acid rain by sharply reducing air pollutants from coal-fired boilers and motor vehicles.

Sponsors called the proposal a "breakthrough" designed to reconcile conflicting regional interests that have blocked acid-rain legislation for five years.

The bill would require deep cuts in industrial emissions, mostly in the Midwest, but it would give states discretion in how to achieve the reductions. It also includes a mechanism designed to cushion the heaviest-hit states from sharp electric rate increases.

"This is a bill that can pass," said Rep. Henry A. Waxman (D-Calif.), who has unsuccessfully led past efforts to enact acid-rain controls. "This is the first step down the road to House action on acid rain."

The bill was quickly endorsed by environmental groups, who called it a strong signal of congressional intent to take action against acid rain. "This bill is the legislative breakthrough we've been waiting for," said Leslie Dach of the National Audubon Society.

Utility representatives, however, said they would oppose the measure. "This bill is going to be more costly than the last one," said William Megonnell of the Edison Electric Institute. "I'm sure these cosponsors have no idea what's going on in this bill."

More than two dozen of its 150 cosponsors appeared at a news conference to endorse the compromise bill, including leading conservative Rep. Newt Gingrich (R-Ga.) and Rep. Morris K. Udall (D-Ariz.), who in the past has opposed any efforts to shift part of the burden for acid-rain controls onto western states.

"It's clear there is a relationship between burning fossil fuels and acid rain," Gingrich said. "We do know enough to do some things."

"As a westerner," Udall said, "I'm here to repent."

Like previous proposals, the new bill would require the electric power industry and other users of coal-fired boilers to reduce their sulfur emissions by as much as 10 million tons over the next decade. Sulfur emissions are believed to be the primary cause of acid rain, which has damaged lakes and aquatic life in northeastern states and Canada and is suspected of damaging forests as well.

The bill would also require reductions in nitrogen oxide emissions, another potential cause of acid rain, from power plants, cars and trucks.

According to a staff analysis by the Office of Technology Assessment, the bill would cost from $3.8 billion to $4.9 billion a year by the early 1990s, and would raise electricity rates an average of 2 to 3 percent.