HOUSTON — It could be several more days before a section of the Houston Ship Channel closed amid cleanup efforts after a fire at a petrochemical storage facility is reopened, a U.S. Coast Guard official said Monday.

The section of the ship channel near the storage facility owned by Intercontinental Terminals Company has been closed since Friday after some oily products leaked into the waterway when a containment area was breached.

Coast Guard Capt. Kevin Oditt said Monday that officials let one ship pass through the affected area Sunday. Oditt said that ship didn’t interfere with the cleanup and its hull did not get contaminated with oil.

Oditt says additional test runs with four more ships and barges were set to be done on Monday.

“The priorities remain ensuring the safety of our on-scene responders as well as mitigating any impact to the waterway or the environment and reopening the Houston Ship Channel,” Oditt said at a news conference Monday.

The San Jacinto River, a waterway leading into the ship channel and located north of ITC’s facility, was reopened to barge and tow traffic but only for about three hours on Monday.

The ship channel is one of the busiest commercial waterways in the country, stretching from the Gulf of Mexico to Houston.

Water samples from the Houston Ship Channel have been tested, but those results are still not complete, said Jeff Kunze, with the Texas Commission on Environmental Quality.

Over the weekend, benzene levels in the air were very high near the site of the fire, but they have dropped significantly, according to monitoring by the Environmental Defense Fund. The group also took water samples in Galveston Bay and is awaiting results.

Adam Adams, with the U.S. Environmental Protection Agency, said air monitoring from his agency as well as several others in the last 24 hours has not found any hazardous conditions that would require warning the public.

“That’s very positive,” Adams said.

The fire destroyed or damaged storage tanks that contained components of gasoline and materials used in nail polish remover, glues and paint thinner. Elevated levels of benzene were detected in the air Thursday, prompting officials to order people to remain indoors for several hours.

Brent Weber, the ITC incident commander at the site of the, said crews on Monday continued emptying the damaged tanks. At least five had been emptied and crews were focusing their efforts on draining two others, Weber said.

The fire and its aftermath prompted several days of canceled classes last week because of concerns over air quality near the facility.

On Monday, students were back in class in Deer Park, Galena Park and other communities near the facility.