CARSON, Calif. — Firefighters made progress Wednesday morning in reducing the size of a fire at the Marathon Petroleum Refinery in Carson that was sparked by an explosion in a cooling tower.

"The fire is nearly out," Los Angeles County Fire Department Inspector Sean Ferguson told NBC4 just after 4 a.m. "We have a little bit of residual fuel still in the pipeline that is burning. However, that should be out in the next hour, completely, we expect."

Air quality in the area was considered safe, but the department recommended, as a precaution, that residents in the area stay indoors.

A refinery safety officers told the fire department monitors reported "no harmful products in the air emanating from the facility, as a result of the fire."

The fire at the refinery at 2350 E. 223rd St., between Wilmington Avenue and Alameda Street and south of the San Diego (405) Freeway, broke out about 10:50 p.m. Tuesday.

"Marathon personnel keeping flames in check via fixed ground monitors while they work to depressurize the system," according to the Los Angeles County Fire Department, which was assisting Marathon crews in extinguishing the flames.

There were no immediate reports of injuries.

All northbound and southbound lanes of the San Diego Freeway at Wilmington Avenue were blocked just after 11 p.m. due to the fire, the California Highway Patrol reported. The northbound lanes of the freeway were reopened about 11:40 p.m. and the southbound lanes reopened about midnight.

Los Angeles sheriff's deputies and CHP officers "secured a perimeter around Marathon Refinery, " the Los Angeles County Sheriff's Department's Carson Station tweeted just before midnight. "We are supporting efforts by (Los Angeles) County Fire & Marathon Facility Fire departments." No evacuations were reported.

The LASD reported some streets were closed in the area:

-- Eastbound 223rd Street at Wilmington Avenue;

-- Westbound 223rd Street at Arco Way;

-- Southbound Wilmington Avenue at the San Diego Freeway;

-- Northbound Wilmington Avenue at Watson Center Drive.

The refinery "is the largest refinery on the West Coast with a crude oil capacity of 363,000 barrels per calendar day," according to the company's website.