[TEXAS CITY] The closure of the vital Houston Ship Channel looked set to extend to a fourth day after the Coast Guard struggled to finish cleaning up after an oil barge spill on Monday, threatening to force deeper production cuts at local refiners.

Earlier on Monday, the Coast Guard had told ship operators that it should be able to reopen the waterway later in the day, resuming at least some supply of crude oil to more than one-tenth of the nation's refining capacity.

"We will begin the process of a tapered ... not a floodgate resumption of marine traffic," Captain Brian Penoyer, commander of US Coast Guard sector Houston-Galveston and captain of the Port of Houston, told reporters on Monday. "We anticipate re-opening the Houston Ship Channel as soon as we can," he said.