By Erwin Seba
HOUSTON, March 24 (Reuters) - No evidence has been found of a deliberate act as the cause of a Monday night explosion at Valero Energy Corp's VLO.N Port Arthur, Texas refinery, said the spokesperson for the Jefferson County Sheriff's office on Tuesday.
"No, we're not investigating it as that," said Donta Miller, chief deputy for the sheriff's office.
The explosion in a diesel hydrotreater was felt 11 miles (18 km) away, said people familiar with plant operations on Monday night.
Valero shut down the refinery to stop the flow of hydrogen or hydrocarbons from fueling the blaze. Hydrotreaters use hydrogen to remove sulfur from motor fuel feedstocks in compliance with U.S. environmental rules.
No injuries were reported and all personnel were accounted for, Valero said on Tuesday.
The refinery is located 86 miles (139 km) east of Houston.
Messages began appearing in online forums on Monday night and continuing into Tuesday suggesting the explosion at the refinery was in retaliation for the U.S.-Israeli attacks on Iran.