The Wall Street Journal reports that several U.S. oil refiners are refusing to sell gasoline containing 15 percent ethanol despite recent government authorization for fuel makers to start distributing the fuel blend.

The three companies - Valero Energy Corp., Marathon Oil Corp. and Tesoro Corp. - own or license their names to a combined 12,700 gas stations in the U.S., about 7.8 percent of the total as of 2008, the latest figure available, according to the Journal article.

The Journal said their refusal could dampen the ethanol lobby's ability to convince the U.S. Environmental Protection Agency to go beyond its existing approval of the fuel blend for vehicles made since 2007. The EPA is weighing whether to expand its approval to older cars and light trucks despite opposition from automakers and some environmentalists.

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