All evacuation orders have been lifted after the chemical tank emergency in Garden Grove

All evacuation orders following a hazardous materials incident at a Southern California airport were lifted Tuesday night, allowing thousands of residents to return home.

Officials have issued a final evacuation order for Garden Grove residents living near a damaged GKN Aerospace Transparency Systems chemical tank that was in danger of exploding.

Authorities said about 50,000 people were ordered to evacuate in and around the Orange County city after a tank containing the highly flammable methyl methacrylate (MMA) overheated and became a hazard.

“All residents will return home,” said Orange County Fire Authority Division Chief Craig Covey during the meeting.

DISNEYLAND REMAINS OPEN AS LANDING GROUND STRENGTHS FOR CHEMICAL TANK SUPPORT

Over Memorial Day weekend, a sudden rupture occurred in the tank, relieving pressure and helping to avoid a catastrophic explosion, allowing many evacuees to return home. However, an estimated 16,000 residents remained under evacuation orders on Tuesday.

Crews continued to pump water out of the tank until the internal temperature stabilized at 92 degrees, down from 100 degrees over the weekend.

The sprinkler system also drained the tank while the company’s technicians and firefighters removed the installation to cool.

COMMERCIAL BUILDINGS CONTINUES IN A NEW WAY, MANY PEOPLE ARE INJURED AND LIVING IN A CRITICAL CONDITION.

Gov. Gavin Newsom has declared a state of emergency in Orange County as California continues to respond to the deadly chemical incident in Garden Grove. (Ethan Swope/AP)

Authorities said the evacuation orders were lifted after the temperature in the tank remained stable for four hours without the aid of a sprinkler.

While health officials assured residents that monitoring did not detect dangerous levels of pollution or smoke, authorities said they would continue to monitor air quality, sewage systems and storm drains for several months.

Exposure to MMA can cause serious respiratory problems, neurological problems, and irritation to the skin, eyes and throat, according to the Environmental Protection Agency.

WORKERS KILLED AND MANY TREATED AFTER CHEMICAL RELEASE AS INVESTIGATORS PROVE CAUSE

Evacuees move to another shelter after a tank leak at an aerospace chemical plant forced the closure of the Garden Grove Sports and Recreation Center in Garden Grove, Calif., on May 22, 2026. (AP Photo/Ethan Swope)

Garden Grove Mayor Stephanie Klopfenstein said she plans to hold the company accountable.

GKN said in a statement on Tuesday that it was continuing to cooperate with the authorities.

“We apologize for the ongoing disruption caused by this incident, and the priority is the safety of our neighbors and our community,” said the statement.

Residents who attended the meeting asked why so many of these chemicals were stored near homes and urged city officials to look closely at the company’s safety measures.

SHOCKING VIDEO SHOWS BLACK PLUME THIRTY-SIXTH LARGE FROM TENNESSEE PLASTIC RECYCLING FACILITY

Water is sprayed from a damaged tank at GKN Aerospace in Garden Grove, Calif., Sunday, May 24, 2026, after a tank containing a chemical used to make plastic parts overheated Thursday. (AP Photo/Ethan Swope)

Crews have been scrambling to contain the catastrophic failure since Thursday, when officials responded to fumes from a storage tank at the facility, which produces engines and products for commercial and military aircraft.

Gov. Gavin Newsom declared a state of emergency on Saturday as crews moved from defensive operations to more dangerous operations aimed at preventing an explosion.

Orange County Fire Authority Chief TJ McGovern told the Los Angeles Times on Tuesday that the problem may have been caused by a failure of a cooling system designed to control the temperature inside the chemical tanks, although officials are still investigating.

He said a malfunction may have caused heat inside the 7,000-gallon pressurized tank of MMA.

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“We don’t know why, but it stopped cooling,” McGovern said. “So that’s what started this event, where the product is hot … and that’s how this whole response started. Now we’re able to get to the bottom, so there’s more to come from what caused it.”

The Associated Press contributed to this report.