A bill to repeal the U.S. oil export ban was expected to pass the House of Representatives on Oct. 9, but faces an uncertain future after a veto threat by President Barack Obama.

U.S. representatives on the morning of Oct. 9 debated the bill, sponsored by Joe Barton a Republican of Texas, and were slated to vote on it later in the day.

Oil policy analyst Kevin Book of ClearView Energy Partners expected the bill to pass the Republican-led House, but said it was unlikely to win the 290 votes necessary to override a White House veto.

Congress passed the ban in 1975 after the Arab oil embargo caused snaking lines at gas stations and fears of global oil shortages.

"Much has changed since the ban on crude was put in place," Representative Fred Upton, a Republican of Michigan, said before the vote. "One of biggest threats to the American energy boom today is not an international actor, but rather our own ban on oil exports."

Backers of repealing the trade restriction say it would keep the drilling boom alive and help U.S. allies find alternative sources of oil beyond Russia and the Middle East.

Opponents of lifting the ban, including the union the International Brotherhood of Electrical Workers, say it will cost jobs in refineries and shipbuilding. Greens say additional energy drilling will harm the environment.

Two similar bills in the Senate have passed through committees but backers are struggling to find enough Democrats to pass legislation in the full chamber.