Ships resumed moving through the Houston Ship Channel late on Friday afternoon as dense fog dissipated along the 53-mile (85 kilometer) waterway to the busiest US petrochemical port, according to the Houston Ship Pilots Association. Pilots are required to steer ships down the 55-foot deep (16.76 meter) Ship Channel, cut in a bay and river averaging 20 feet (6.10 meters) in depth.
Dense fog rolled into the Houston area late on Friday morning and visibility reached nearly zero on a six-mile (9.6 km) portion of the Channel, according to the US Coast Guard Houston Vessel Traffic Center.
The area closed in by fog was south of the Ship Channel's refinery row, meaning tankers may not have been able to reach Houston-area refineries for about four hours.