Tesoro refinery explosion, fire prompt order to shelter in place in Wilmington

A tank exploded Friday at the Tesoro refinery in Wilmington, spewing hazardous sulfur dioxide and hydrogen sulfide vapors into the community and causing massive gridlock along nearby roads.

Refinery officials said the lid of the tank was somehow breached at about 1 p.m., causing a chemical explosion that set the tank’s insulation on fire, said county fire and Tesoro officials.

The refinery along South Alameda Street, which borders densely populated neighborhoods in Carson and Long Beach, alerted the community to “shelter in place” while an investigation took place.

Smoke billows after an explosion and fire at the Tesoro refinery Friday, August 26, 2016, Carson, CA. The fire caused evacuations and a hazardous materials response which was later lifted. No injuries were immediately reported. Photo by Steve McCrank/Staff Photographer

Smoke billows after an explosion and fire at the Tesoro refinery Friday, August 26, 2016, Carson, CA. The fire caused evacuations and a hazardous materials response which was later lifted. No injuries were immediately reported.

A fire in the sulphur tank was quickly extinguished.

“There is a visible steam plume over the unit, which responders are working to discontinue,” Tesoro spokesman Ken Dami said about five hours after the explosion. “We have and are continuing to conduct air quality monitoring around the site, and at this time we have not detected any harmful level of toxins.”

No injuries were reported in the incident, and Dami said officials found no cause for alarm in air-quality tests throughout the afternoon. He said it will be “some time before we get to the root cause” of the explosion.

The shelter-in-place advisory was canceled about 6:30 p.m., according to a lieutenant at the Carson sheriff’s station.

Alameda Street was closed between 223rd Street and Sepulveda Boulevard until 7:30 p.m. The closure caused gridlock through rush hour on the streets in the area, which is up against the 405 and 710 freeways. The street was reopened when the steam plume was contained by a unified command of Los Angeles County fire, hazardous materials and sheriff’s officials working with Tesoro’s emergency responders.

The refinery is about to embark on a major renovation and expansion. Tesoro is merging its two neighboring plants in Carson and Wilmington, creating the largest refinery on the West Coast. It purchased the former BP refinery in Carson in 2012. Together, the two refineries process about 360,000 barrels of crude oil a day.

Tesoro anticipates spending $460 million on modernization efforts at the massive 1920s-era plants. The company hopes to greatly increase its storage capacity and build a new sulfuric acid regeneration plant so it can recycle the sulfur it removes from crude oil rather than trucking it away

A new jet-fuel treatment facility, railcar-unloading facilities, and propane sales treating unit are also planned. One of the two refinery catalytic cracking units is also set to be removed.

The refinery plays a key role supplying fuel for vehicles in Southern California.

“One in three cars has our fuel in it in Southern California,’’ Dami said.