Williams Partners LP’s Ohio Valley Ethane Pipeline is still out of service as the company assesses damage from a fire that broke out at a metering station on Christmas Eve in southwest Pennsylvania, a company spokeswoman confirmed Tuesday.

The cause of the fire remains unknown. The company’s pipeline control center received an alarm at 10 p.m. EST Dec. 24, prompting employees to close the main line valve in order to stop the flow of ethane, said Williams spokeswoman Sara Delgado. No injuries were reported.

“Williams personnel and local emergency responders worked in coordination at the site,” Delgado said in an email. “As a precaution, emergency responders evacuated approximately a dozen homes in the vicinity. Residents were allowed to return to their homes at approximately 12:30 a.m.”

The 50-mile, 12-inch diameter pipeline provides ethane transportation from Williams’ Oak Grove natural gas processing facility in Marshall County, WV, to an ethane hub in Houston, PA, where volumes are sent through interconnections northward to petrochemical markets in Canada.

The fire broke out at a metering station in Chartiers Township, about four miles from Houston, PA. Delgado said an investigation into what caused the fire is under way and said it was unclear when the pipeline might be back in service.