MEDFORD, Okla. (AP) — Officials say Oklahoma Natural Gas crews have contained a propane leak that prompted a voluntary evacuation of a northern Oklahoma town.

ONEOK spokeswoman Megan Washbourne and Medford City Manager Dea Kretchmar said workers were still trying to cap the leak Sunday. Washbourne said they were waiting for a part to finish the job.

The leak began Tuesday at a fuel-storage plant owned by ONEOK, which is ONG's parent company. Medford residents were evacuated out of concern that the vapors could pose a fire risk if a pocket of propane ignited.

The Environmental Protection Agency said contractors planned to pump a brine and mud mixture into an underground well to stop the leak.

Kretchmar says residents who left their homes returned by Sunday.