Nov. 30 (Bloomberg) -- Gulf Coast diesel slipped to the lowest level against futures since January after Valero Energy Corp. restarted a hydrotreater and Total SA’s operations returned to normal at its Port Arthur refinery in Texas.

Valero started the hydrotreater after work on a compressor was completed, Bill Day, a company spokesman in San Antonio, said in an e-mail Nov. 28.

The discount for ultra-low-sulfur diesel in the Gulf Coast widened 1.2 cents to 3.75 cents a gallon versus futures trading on the New York Mercantile Exchange at 1:52 p.m., according to data compiled by Bloomberg. It is the lowest level since Jan. 31. Prompt delivery rose 0.37 cent to $2.9993 a gallon.

Operations at Total’s Port Arthur plant in Texas returned to normal at 10:15 a.m. local time after an upset at 9:53 a.m. during preventative maintenance on the fluid catalytic cracker, Jennifer Walsh, a spokeswoman for the company in Houston, said in an e-mail.

The discount for conventional, 87-octane gasoline in the Gulf widened 0.1 cent to 5.6 cents a gallon versus futures.

--Editors: Richard Stubbe, Margot Habiby

To contact the reporter on this story: Paul Burkhardt in New York at pburkhardt@bloomberg.net.

To contact the editor responsible for this story: Dan Stets at dstets@bloomberg.net.