(Adds details, background on other Williams explosions)
May 1 (Reuters) - Williams Partners LP said on Thursday it brought back into service two of the five units at its Opal, Wyoming, gas processing plant that has been shut since one unit was damaged in an explosion and fire on April 23.
Williams Partners, which is majority owned by Williams Cos Inc of Tulsa, Oklahoma, said in a statement it returned units 1 and 2 at Opal. Unit 3 was the unit damaged by the explosion and fire.
The April 23 incident at Opal was the second explosion and fire to shut a Williams gas facility in a month, leading some to worry that incidents like these will make it tougher for the industry to replenish stockpiles drained to critically low levels after a brutal winter.
Williams said units 1 and 2 have a combined design processing capacity of 395 million cubic feet of gas per day.
Units 4 and 5, meanwhile, remain offline as the company takes the necessary steps to bring additional portions of the plant into service, Williams said.
At the time of the incident, Opal was processing daily inlet volumes of approximately 1 bcf of gas. The capacity of the four undamaged units 1, 2, 4 and 5 totals 1.1 bcf per day, which Williams said is sufficient to handle all of the gas currently available to the facility.
Unit 4 was idle at the time of the fire, serving as excess capacity for the facility.
Williams said its initial visual assessment of damage indicates that the impact was largely limited to a small area of Unit 3 due to a release of gas that was subsequently ignited.
The company said it is working with regulators to investigate the cause of release and source of ignition.
The company said it has insurance, subject to deductibles, for property damage and business interruption and expects the coverage to mitigate the financial effects of the incident.
The company also said it is working to address the needs of customers whose business is affected by the temporary shutdown of the Opal facility.
Separately, Williams said it continues to investigate the cause of the March 31 explosion and fire that shut its liquefied natural gas storage facility in Plymouth, Washington.
The company said it is focusing on a failed pressure vessel that removes carbon dioxide from the gas prior to its being liquefied.
The explosion of the vessel sent shrapnel across the facility, including into one of the plant’s two LNG tanks, damaging at least the outer shell of the tank. The company has said it will confirm the integrity of the inner shell of the damaged tank after it transfers the LNG to the undamaged tank.
Each tank at Plymouth is capable of holding 1.2 bcf of gas.
The company could not say when the Plymouth facility will return to service, noting the investigation “may continue for several months” while site materials are submitted for analysis. (Reporting by Scott DiSavino; Editing by Chizu Nomiyama)