The Senate dropped efforts late Monday to pass energy legislation this year after Republican leaders failed repeatedly to find the two additional votes needed to push the bill through Congress.

Top GOP senators couldn't root out the additional votes among farm-state Democrats, while House Republican leaders balked at a change in the bill that would have removed a provision protecting makers of a gasoline additive, MTBE (search), from pollution lawsuits.

The MTBE liability shield had been at the heart of widespread Senate opposition to the $31 billion energy legislation which included hundreds of provisions aimed at boosting and diversifying energy production. The House passed the bill easily.

Majority Leader Bill Frist (search), R-Tenn., concluded there was not enough time before the Senate was to begin its holiday recess to find a compromise that would be acceptable by the House and overcome a Democratic-led filibuster (search) in the Senate.

Bush administration officials said the White House was ready to push for the legislation in January, confident that Republican leaders will be able to get the support needed to pass the bill by then.

"Although Sen. Frist remains committed to the energy bill, it appears in the short time we have left before we recess for the holiday, we will not be able to take up the energy legislation again," a spokeswoman for the GOP leader said.

The spokeswoman, Amy Call, said that work would continue over the recess period "to bring all sides to an agreement."

The House easily passed the massive energy bill last Tuesday, but when it came to the Senate a coalition of Democrats and Republicans, for different reasons, joined in blocking further action.

An attempt on Friday to shut off debate and bring the measure up for a final vote fell two senators short of the 60 needed. Repeated attempts failed over the weekend to find two lawmakers willing to change votes, GOP sources said.

On Monday, the White House stepped up pressure on House Republican leaders to support a proposal that would strip away a controversial provision in the bill that would give manufacturers of a gasoline additive, MTBE, protection against environmental lawsuits.

The MTBE issue prompted widespread criticism of the massive bill when it came before the Senate.

While progress was being made in the House to try to strip out the MTBE liability language, it became increasingly clear late Monday that Republican leaders were not going to get the votes needed in the Senate.

The GOP source said several Democrats had expressed a willingness to shift their votes and support the energy bill if the MTBE liability provision was taken out, but backed away from the idea after Republicans won a key vote on a prescription drug bill.

"It was like a door slamming shut," said the source, who spoke on condition of anonymity.

A Senate Democratic source, who also declined to be identified, said there has been no movement among senators on the energy bill despite intense lobbying over the weekend.

Opponents of the MTBE provision said it would leave communities and water users to pay for cleaning up MTBE contamination of drinking water supplies in dozens of states.

Mayors, local officials and water managers have estimated that the cost of cleanup from MTBE in drinking water supplies could reach $29 billion.

The Bush administration, with Energy Secretary Spencer Abraham spending much of his time on Capitol Hill and talking to lawmakers by phone, stepped up pressure on House Republican leaders to agree to drop the MTBE liability language.

But two key House Republicans -- Majority Leader Tom DeLay and Rep. Joe Barton, both from Texas, where most MTBE is produced -- continued to balk at removing the provision. House Speaker Dennis Hastert, R-Ill., had indicated a willingness to do so, according to a GOP source close to the discussions, but only if it became clear the Senate had the votes to pass the bill.

Once viewed as key to reducing air pollution from cars, MTBE became an object of scorn when it was realized it was difficult to contain and clean up once it gets into drinking water. Traces have been found in almost every state and it has the potential of becoming a cleanup problem in at least 28 states, according to government and private studies.