Evacuation orders impacting approximately 40,000 residents were issued Friday in Garden Grove, California, after a chemical tank at an aerospace facility entered a critical state, with officials warning it could either fail and spill its contents or explode.

Firefighters initially responded Thursday to a leak at GKN Aerospace, an aerospace manufacturing company, where vapor was releasing from a 34,000-gallon tank containing methyl methacrylate. Officials from the Orange County Fire Authority stated Friday that while there is no active gas leak or plume, the tank is in crisis and cannot be secured due to damage to a valve.

Orange County Fire Authority Division Chief Craig Covey described the dire situation, stating that the tank has two potential outcomes: a failure leading to the spill of 6,000 to 7,000 gallons of chemicals into the parking lot, or a thermal runaway event that could cause an explosion affecting surrounding tanks containing fuel or other chemicals. He emphasized that evacuations are a preparation for these possibilities, not a precaution.

Authorities reissued and expanded evacuation orders Friday after initially lifting a smaller order Thursday when vapor conditions improved. The situation is described as unprecedented, with the chemical being highly volatile, toxic, and flammable. Officials stated it is unclear when residents will be allowed to return home.

The tank in question experienced an increase in temperature and began to bulge on Thursday. Efforts to neutralize the chemical have been ineffective, and the damaged valves prevent the substance from being removed. Covey confirmed that two other tanks at the facility do not present concerns.

The Garden Grove Unified School District reported that over a dozen schools have temporarily closed, and schools near the evacuation zone are canceling outdoor activities. Methyl methacrylate is an industrial chemical commonly used in plastics and manufacturing, primarily acting as a respiratory irritant, according to authorities.

The evacuation order on Thursday was lifted due to improved vapor conditions, but the escalating crisis with the compromised tank led to the reissuance of broader evacuation orders. Officials stressed the urgency and the non-precautionary nature of the current evacuation.

Officials have reached out to GKN Aerospace for comment. The volatile nature of the chemical and the potential for a catastrophic event underscore the severity of the ongoing hazmat incident.