HOUSTON (Reuters) – The backlog of vessels waiting to move through the Houston Ship Channel grew on Monday while it remained closed to traffic for a third day as emergency workers attempted to clear a petrochemical spill from the Intercontinental Terminals Co (ITC) storage facility in Deer Park, Texas, the U.S. Coast Guard said on Monday.

Thirty-one vessels waited to enter the busiest U.S. oil port on Monday, while another 31 waited to leave, up from 26, respectively, on Sunday morning. The seven-mile (11-km) section of the Houston Ship Channel from Light 116 to Tucker’s Bayou remained closed, said Coast Guard Vessel Tracking Service Watch Supervisor Ashley Dumont.

Fuels spilled after a 10-foot (3-meter) wide section of a containment barrier breached on Friday at Mitsui & Co Inc’s ITC facility outside of Houston, sending fuel, water and fire suppressant foam to a waterway that connects Houston to the Gulf of Mexico.

The Coast Guard opened the San Jacinto River to allow two-way vessel traffic for three hours until 12 p.m. CDT (1700 GMT)on Monday. The Texas Commission on Environmental Quality continued to assess the contamination levels in the channel. The Coast Guard did not have a timeline to reopen the port, Dumont said.

(Reporting by Collin Eaton in Houston; Editing by Chizu Nomiyama and Marguerita Choy)