LOS ANGELES (CN) — Southern California regulators must put the brakes on an ExxonMobil refinery that emits 50 tons of hydrogen cyanide in Los Angeles each year, the Refinery Safety Network says in court.

The nonprofit sued the South Coast Air Quality Management District on Wednesday in Superior, and named ExxonMobil Oil Corp. as a respondent-real party in interest.

The SCAQMD regulates air in one of the most polluted areas of the nation: all of Orange County and the urban parts of Los Angeles, Riverside and San Bernardino counties.

In early April the co-defendant SCAQMD Hearing Board issued an abatement order that allows ExxonMobil to operate a fluid catalytic cracking unit at a refinery in Torrance without air pollution control devices.

That violated multiple district rules, the state health and safety code and the California Environmental Quality Act, the network says.

The refinery, built in 1929, covers 750 acres, employs 650 workers and 550 contractors, processes 155,000 barrels of crude oil a day, and produces 1.8 billion gallons of gasoline a year.

“The abatement order allows the violation of 11 district rules, one district administrative condition, and California Health & Safety Code section 41701, allowing excess emissions of nitrogen oxides, particulate matter, particulate matter of less than 10 microns in diameter, and carbon monoxide,” the 13-page complaint states. (Citations omitted.)

Refinery Safety Network member Cara Petrat cited the health risks in a submission to the board by non-party Mothers of the South Bay. But the board refused to address those concerns through an Environmental Quality Act review, according to the complaint.

ExxonMobil restarted the Torrance refinery after an explosion rained catalyst ash miles from the refinery and injured two workers in 2015.

The U.S. Chemical Safety Board is investigating the incident, Refinery Safety says.

The safety board said in January that that the explosion occurred in the refinery’s electrostatic precipitator, which controls air pollution.

“That investigation has disclosed that because of the explosion, an 80,000 pound piece of debris landed on temporary scaffolding which was around a pressurized tank called a ‘settler’ tank containing tens of thousands of pounds of modified hydrofluoric acid, an extremely toxic substance which if released could have led to the injury and deaths of hundreds of thousands of community members around the refinery,” the lawsuit states.

Chemical Safety Board Chairwoman Vanessa Sutherland said hydrofluoric acid “can pose a severe hazard to the population and environment if a release occurs.”

“After [hydrofluoric] acid vaporizes it condenses into small droplets that form a dense low-lying cloud that will travel along the ground for several miles and can cause severe damage to the respiratory system, skin, and bones of those who are exposed, potentially resulting in death,” Sutherland said in a statement.

Torrance, pop. 147,000, is an affluent coastal community in southwestern Los Angeles County, with industrial areas next to residential zones.

Refinery Safety said the abatement order would allow excess emissions of hydrogen cyanide, “an extremely toxic pollutant used in the gas chambers of Nazi Germany.”

“During the restart of the refinery, ExxonMobil has gotten clearance from SCAQMD not to run the CO [carbon monoxide] boiler, a pollution device that can limit emissions of HCN [hydrogen cyanide] to the extent that the FCCU’s [fluid catalytic cracking unit’s] regenerator generates HCN,” the lawsuit states.

Representatives for the Refinery Safety Network, ExxonMobil and the SCAQMD could not immediately be reached for comment Thursday.

Non-party PBF Energy wants to buy the Torrance refinery from ExxonMobil, under conditions that it be repaired before the deal closes.

Refinery Safety seeks a stay of the abatement order.

It is represented by Craig Collins with Blum Collins.