A Senate committee approved legislation Thursday to open the Arctic National Wildlife Refuge to oil exploration, rejecting an amendment to delay it until a national energy plan is developed.

The Senate Committee on Energy and Natural Resources adopted a proposal by Sen. Mark Hatfield, R-Ore., that would allow drilling while a study on energy conservation is under way.An amendment to the bill that would have delayed any drilling until the interior secretary presented Congress with a comprehensive energy plan was defeated on a 12-7 vote.

Committee Chairman Bennett Johnston, D-La., called the amendment, offered by Sens. Timothy Wirth, D-Colo., and Dale Bumpers, D-Ark., a "killer amendment" that would effectively stop any oil drilling in the refuge.

"We have been studying energy policy in this committee for 17 years," Johnston said. More conservation is needed, he said, but in the meantime more domestic oil production must begin.

Estimates as to the amount of oil that may be found in the refuge vary, with the minimum put at 3.2 billion barrels.

The bill, which pits conservationists against development interests, now goes to the Senate floor for a vote. It has not been taken up by the House.

The measure was introduced last session, but failed to get a vote on the floor of either the House or Senate.

On Wednesday, the committee refused to tie a requirement that cars be more fuel efficient to the drilling legislation.

That amendment, offered by Sen. Howard Metzenbaum, D-Ohio, said American cars would have to get an average 34 miles to the gallon by the year 2000, or the manufacturer would be penalized.

"We would get more oil from the Metzenbaum amendment than we would from ANWR (the wildlife refuge)," said Wirth.

Bumpers said he might be persuaded to vote in favor of searching for oil in the refuge, "but it doesn't make sense to use it in gas guzzlers."

He said Americans have "gotten fat and happy," are buying big cars and are not serious about dealing with "an energy crisis that is coming just as certainly as God made little green apples."