* Valero completed Port Arthur refinery shutdown on

Tuesday

* Fire extinguished at Texas refinery

* No injuries reported from blast, blaze

By Erwin Seba

HOUSTON, March 24 (Reuters) - A release of fluid set off

an explosion and ensuing fire that forced the temporary shutdown

of Valero Energy Corp's ( VLO ) 380,000-barrel-per-day (bpd) oil

refinery in Port Arthur, Texas, according to a notice the

company filed with state pollution regulators on Tuesday.

No injuries were reported from the explosion in the

47,000-bpd unit 243 diesel hydrotreater, the people said. No

date has been set for restarting the refinery.

"An unforeseeable release of process fluid in Complex 2

resulted in an ignition event and multiple process unit upsets,"

Valero said in the notice filed with the Texas Commission on

Environmental Quality (TCEQ) on Tuesday evening.

The refinery outage comes as U.S. consumers contend with

rising gasoline and diesel prices because of Iran's closure of

the Strait of Hormuz, a key oil and refined product waterway for

Middle East producers, in retaliation for U.S. and Israeli air

attacks.

Donta Miller, the chief deputy for the Jefferson County

Sheriff, said on Tuesday there was no evidence the Monday night

explosion felt as far as 11 miles (18 km) away, was the result

of a deliberate act by someone intending to damage the refinery.

Since Monday night, posts online have claimed the Port

Arthur refinery explosion was the result of sabotage by either

Iranian or Israeli agents.

"No, we're not investigating it as that," Miller said.

Shutting the refinery was seen as necessary to extinguish

the fire, the sources said, by cutting off flammable materials

feeding the flames. The refinery lost water supply and steam as

firefighters battled the blaze.

Diesel hydrotreaters use hydrogen to remove sulfur from motor

fuels during their production to comply with U.S. environmental

rules.

The fire was put out on Tuesday and a shelter-in-place

order for west Port Arthur residents issued at about 6:20 p.m.

CDT (1120 GMT) on Monday was lifted shortly before 6 a.m. CDT on

Tuesday.

According to the TCEQ filing, the Valero refinery's large crude

distillation unit, gasoline-producing fluidic catalytic cracker,

diesel-producing hydrocracker, cokers, sulfur recovery units,

hydrotreaters, reformer and alkylation unit were shut.

Valero's Port Arthur refinery, the company's largest, is

situated 86 miles (138 km) east of Houston.