A Marathon Petroleum Corp. oil refinery on the Texas Gulf Coast continued to leak crude into the surrounding area more than 24 hours since the spill first began, a regulatory filing from the company showed.

The incident at the Galveston Bay facility in Texas City was caused by a failure of a valve flange and led to crude oil being released into a containment dike, the filing with the Texas Commission on Environmental Quality showed. The storage tank holding the oil is being emptied as quickly as possible to minimize pollution. No one was injured.

The leak at the 593,000 barrel-a-day refinery is being contained within an earth dike and foam is being applied to reduce vapors. Equipment to remove the oil for processing and disposal is being deployed.

Crude oil released from the storage tank remains contained on-site, and there has been “no indication of risk to the community,” spokesman Jamal T. Kheiry said in an emailed statement on Thursday. The company still doesn’t have an estimate on how much oil has been lost, he added. 

Shares of Marathon, the largest independent U.S. refiner, fell 1.1% as of 8:41 a.m., before regular trading hours.

The incident started at 7:30 a.m. local time on Wednesday and is expected to be over by 7:30 p.m. Thursday, the filing showed. It estimated the leakage at 5,000 pounds of volatile organic compounds.

A road running by the site was closed because of odors emanating from the spill, Bruce Clawson, emergency manager for Texas City, said Wednesday.