Nov. 20 (Bloomberg) -- The Houston Ship Channel, which serves the largest U.S. petroleum port, may reopen to inbound oil tankers and other vessels this morning after being closed more than 31 hours because of fog.

Forty-four inbound and 18 departing vessels remain idled, T.J. Nelson, spokesman for the Houston Pilots Organization, said today in a telephone interview. When the channel reopens, he said, five inbound tankers will be brought in first. One of those ships is carrying liquefied natural gas.

The 54-mile (87-kilometer) waterway was closed to ships at 1:05 a.m. yesterday by the Houston Pilots Organization. The pilots reopened the channel to outbound traffic from 12:30 p.m. to 7:19 p.m., while keeping it closed to most inbound traffic.

Fog has been getting heavier since about 7:30 a.m. local time and may prevent pilots from moving ships through the waterway this morning as they had planned, said Garry Jarvis, a U.S. Coast Guard spokesman.

The Houston Ship Channel typically has 55 vessel movements a day. It takes two to three days before a channel shutdown begins to affect operations at Houston-area refineries.

Houston has the largest U.S. oil port and second-biggest port of any kind by tonnage. More than 420 petrochemical plants and two of the nation's four biggest oil refineries are in the Houston area, according to the Greater Houston Partnership.

To contact the reporter on this story: Victor Epstein in Houston at vepstein@bloomberg.net.

Last Updated: November 20, 2007 09:55 EST