The leak was reported at Marathon Petroleum’s Galveston Bay Refinery in Texas City, Texas, on Wednesday morning.

Aerial video broadcast by local television stations showed what appeared to be gallons of brown crude oil spilling from the tank at the 593,000-barrel-a-day refinery, filling an earthen berm that is designed to contain spills.

The Texas City Emergency Management Department closed roads near the refinery to all but essential traffic on Wednesday in response to the leak, according to Click2Houston.

The department reported that the tank had stopped leaking by early Thursday, but said roadways would remain close as clean-up efforts continue.

“The crude oil tank has stopped leaking,” the department said in a Twitter post. “However, the south loop remains closed and will remain closed for the next two days while crews clean up the site.”

The tweet added: “All spilled crude oil was contained on the site and will be removed, properly treated and the roadway safely reopened.”

Joe Gannon, a spokesperson for Marathon Petroleum, told Newsweek that all spilled oil had been contained on-site and there appears to be no risk to the public.

“In response to a crude oil release from one of its Galveston Bay refinery storage tanks yesterday, October 6, Marathon Petroleum personnel implemented measures to control the source of the release and have begun to conduct cleanup activities,” Gannon said in a statement. “There have been no injuries, and crude oil released from the storage tank remains contained on-site.”

Gannon said the refinery “deployed air monitoring in the community as a precaution, and the monitoring continues,” but added that “there has been no indication of risk to the community.”

The company does not yet have an estimate on how much oil was leaked, Gannon said.

He added: “Regulatory notifications were made and an investigation will be conducted to determine the cause of the release. The safety of our employees, responders, and the community is our top priority as we respond to the release, conduct cleanup activities, and continue to coordinate with local, state, and federal regulatory officials.”

According to a regulatory filing from the company with the Texas Commission on Environmental Quality, the leak was caused by a failure of a valve flange, Bloomberg reported.

The filing estimated the leakage at 5,000 pounds of volatile organic compounds.