The toxic chemical leak at the GKN Aerospace facility in Garden Grove, California, on the afternoon of Thursday May 21 triggered subsequent explosion fears as around 40,000 Southern Californians were given orders to evacuate.

Given the worsening situation, the authorities are highly concerned that the tank with a toxic chemical, named methyl methacrylate (MMA) will explode.

Hazmat experts have been working tirelessly to prevent chemical leakage that could explode or potentially ignite a massive fireball at a plant in County, Calif. Evacuation orders were issued to those in the 9-square-mile area around the facility involved, impacting over 40,000 residents.

Authorities evacuated 13 schools and two facilities within the Garden Grove Unified School District on Friday morning.

According to Orange County Fire Authority Division Chief and Unified Incident Commander Craig Covey, who gave a recent update on Friday evening related to decreased temperature of the tank.

“It’s down to a temperature around 61 degrees, with 50 being its happy place,” Covey said.

The decreased temperature of the tank is “giving us an opportunity to reconsider engaging in close proximity to implement some of the concepts that were outside the box,” Covey added.

What caused this situation?

The tragic incident began when a storage tank containing thousands of gallons of MMA began to overheat and started venting hazardous vapours. As per reports, the overheating was triggered by the failure of the tank's cooling system.

When the emergency crew came to know about the leak, initially attempted to stabilize the situation and cool the tank, their efforts were complicated by an inoperable valve on the tank.

This damage prevented crews from safely accessing or neutralizing the material inside, leading to worsening conditions that necessitated the expansion of evacuation orders on Friday.

Growing explosion risks

Covey discussed the growing risks associated with the overheating of the tank. If the tank cracked, it could spill up to 7000 gallons of toxic chemicals. In severe cases, it could blow up and endanger neighbouring tanks.

The Orange County Fire Authority (OCFA) also warned of growing explosion risks due to self-heating properties of MMA. In the case of failure to maintain temperature, the chemical can undergo a thermal runaway reaction.

Methyl methacrylate is highly volatile and flammable industrial chemical used to manufacture acrylic plastics.