With proven U.S. crude oil reserves increasing, Senate leaders said it was time to lift a 1970s era ban restricting crude oil exports.

The U.S. Energy Information Administration reported proved crude oil reserves in 2012 reached 33 billion barrels, 15 percent more than the previous year and the fourth consecutive year for an increase.

Sens. Mary Landrieu, D-La. and Lisa Murkowski, R-Alaska, called on EIA Administration Adam Sieminski to consider lifting an export ban imposed in response to the Arab oil embargo in the 1970s.

Of particular interest were the economic impact of keeping the ban in place, how competitive U.S. crude oil would be on the global market and what logistics were needed to reverse the ban.

"You know better than most the true magnitude of the North American energy renaissance," they said in their Friday letter to Sieminski.

Murkowski, ranking member of the Senate Energy and Natural Resources Committee, heard testimony in January about the prospects of exporting more crude oil. Industry officials said exposing U.S. crude oil to a global market would expose the economy to more overseas shocks.

There was no EIA comment on the oil export request.