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Carson Refinery Fire: What We Know So Far And What It Means For Gas Prices

The scene at a fire that broke out late Tuesday night at the Marathom Refinery plant in Carson. (Courtesy of NBC4)
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Firefighters are on scene at the Marathon Petroleum refinery in Carson this morning where a dramatic fire broke out just before 11 p.m. last night. Huge flames and plumes of smoke could be seen for miles and witnesses reported hearing explosions.

As of mid-morning, the fire was contained and under control, all personnel were accounted for, and no injuries had been reported, according to a statement from the refinery. The fire did force the company to shut down a portion of the refinery.

"The safety of our employees and the surrounding community is our top priority," the company said.

The company said it had set up an emergeny operations center and that L.A. County firefighters were ready to assist the refinery's team if needed.

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The cause of the fire is under investigation but officials earlier said it appeared there was an explosion in a cooling tower.

The refinery also said that air monitoring was ongoing and that no risk to the community has been identified.

Click "Read More" below for additional coverage on:

  • Why residents didn't receive alerts
  • What we know about Marathon and this refinery
  • What was released into the air
  • What it will mean for gas prices
  • What we might expect from the investigation

The 405 Freeway and some surrounding streets were shut down in the area briefly Tuesday night, according to the California Highway Patrol, but those roads have since reopened. The facility is located on 223rd Street, between Wilmington and Alameda, south of the 405 freeway.

According to an AQMD map, the air quality rating in the area is moderate, still officials are asking nearby residents to stay indoors as a precaution.


Carson Mayor Albert Robles said he was concerned that city residents did not receive text message notifications of the explosion and fire.

“If we can do an Amber Alert in geographic areas, if we can do flood warning alerts that geographic areas, why can't these warning systems be implemented in these types of situations?” Robles said.

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That system is operated by the L.A. County Sheriff’s office, if and when requested by the county Fire Department incident commander, said Helen Chavez, associate director for the L.A. County Office of Emergency Management. In this case, the decision was made to not send an alert, she said.

Instead, fire and emergency responders relied on social media, TV and radio news outlets and on-scene interviews to inform the public.

Carson resident Dianne Thomas said that’s how she realized the quake she felt was actually a refinery explosion.

“So, I’m sitting in my house and there’s a major BOOM. My house shook and all that,” Thomas said.


The Marathon refinery in Carson is one of 17 refineries located in California, and the largest on the West Coast, with a crude oil capacity of 363,000 barrels per calendar day.

  • Overall, California refineries produce 2 million barrels a day, so an interruption in the supply from the Marathon Petroleum refinery in Carson represents about 18% of the state’s daily fuel production.
  • Marathon Petroleum says it is the nation’s largest fuel refiner, and nationally, it produces about 3 million barrels of fuel.
  • After an explosion and fire in 2015 at a Torrance refinery, neighbors started advocating for more transparency and raised serious questions about safety concerns. Will we see the same reaction here?

Marathon Petroleum considers two refineries in Carson and Wilmington to be a single operation after merging the two plants in 2019. They have been parts of the Southern California industrial landscape for many decades.
The Carson refinery goes back to before World War II, starting out as a Richfield Oil Corp. refinery in 1938. It became part of ARCO in 1966, then PB West Coast Products in 2000. Tesoro Refining acquired it in 2013, and then a company called Andeavor picked it up in 2017. Marathon Petroleum took ownership in October 2018.

Marathon Petroleum’s Wilmington Refinery is even older, dating to 1923 when it was built by California Petroleum Corp. It was bought by Texas Co. in 1928, which became Texaco Inc in 1959. A joint venture of Texaco and Shell Oil called Equilon Enterprises operated the refinery from 1998, and then it reverted to Shell ownership in 2002. Tesoro Refining took over in 2013, passed it on to Andeavor in 2017 and to Marathon Petroleum in October 2018.


The report that refinery staff called in to the state Office of Emergency Services said the explosion and fire at the refinery was causing the release of more than 500 pounds of sulfur dioxide, which can harm the eyes, skin and lungs, depending on the concentration.

The South Coast Air Quality Management District sent inspectors to grab air samples from the Carson refinery fire to be analyzed for benzene, tetrachloroethylene (perc), toluene and styrene. An AQMD statement said Marathon Petroleum's fenceline air monitors "show no elevated levels of gaseous air toxics."

The AQMD is also sending its mobile air quality monitor to check for pollutants in communities outside the refinery.

Air quality monitors are posted along the fenceline of Marathon Petroleum's Carson refinery.


Marathon officials have told reporters that because the fire involved methane — natural gas — and "light hydrocarbons" and not refined fuel, the fire should not lead to a spike in gas prices. Our infrastructure reporter Sharon McNary notes: "From the outside, it’s hard to know if that’s just corporate happy talk or an accurate forecast."

What we’ve seen in past local refinery fires or explosions — when it shuts down production, sometimes for weeks, months, or even a year. We saw that with the explosion at the Torrance refinery in 2015. That incident led to gas price spikes of up to 30 cents a gallon.

Why? Well any shutdown lowers the supply of locally refined fuel, and lower supply means higher prices.

Here in California we are especially vulnerable to those price swings based on local supply because we have special formulations to reduce emissions, so we don’t just haul it in from Texas where they aren’t so concerned with air quality. Also, most of the fuel that’s refined locally is imported from afar, not extracted in Southern California, and for that reason the industry says we are a “fuel island.”

Another thing to note: In March and April refineries switch from their winter to summer fuel blends. The refinery had announced last week that it would be flaring off excess hydrocarbons in the plant starting on Monday and continuing through March 4. It’s not clear right now where the refinery was in this process or why it was doing the planned flaring.


Another factor with this fire is what kinds of investigations and penalties might follow. We’re talking a look at the pollutants the refinery fire put into the air.

Authorities will need to know more about what happened and that is likely to come from the various agencies that will converge on the refinery operators for answers – AQMD, California Air Resources Board, OSHA, U.S. Chemical Safety Board and so on.

The refinery has faced penalties for violations from the California Air Resources Board in 2018 and 2019 when it exceeded certain limits.


Reporter Sharon McNary is talking to officials and safety experts and reporting on the background of this refinery. Producers Brianna Flores and Pablo Cabrera have been reaching out to refinery, fire and other authorities for updates on the fire.