Congressional leaders have signaled their agreement to lift the 40-year-old ban on oil exports out of the United States.

The bill allowing oil exports is in the middle of a congressional deal on spending and tax legislation that was announced early Wednesday.  Both the House and Senate still must pass it and President Obama must sign it into law – but all are expected to sign it as of this morning.

The bill adopts environmental and renewable measures that Democrats sought.  These include extending and then phasing down wind and solar-tax credits; reauthorizing a conservation fund; and excluding any measures that block major Obama administration environmental regulations.

President Obama had threatened to veto separate legislation lifting the export ban, but the White House isn’t expected to oppose the overall spending bill simply because it includes the measure, according to congressional aides.

Congress banned oil exports under most circumstances following the 1973 Arab oil embargo that sent domestic gasoline prices skyrocketing.

The U.S. is already exporting approximately 400,000 barrels of crude a day to Canada, the biggest exemption under the current ban.  That is more than nine times as much as in 2008 but still just 3.8% of the U.S. oil produced every day.

Extensive networks of oil pipelines and storage tanks already stretch along the Gulf Coast from Corpus Christi, Texas, to St. James Parish, Louisiana.  Approximately 30% of the United States refineries are located in this area.  Those oil ports are currently only designed for unloading crude from tankers, not loading them.  So there would be some retrofitting necessary to allow these facilities to load oil into the tankers.