California officials announced on 24/5 that firefighters accessed and discovered a crack on a tank containing 26,500 liters of methyl methacrylate (MMA) in Garden Grove, Orange County.

"The crack may help relieve some internal pressure," stated TJ McGovern, acting fire chief for the Orange County Fire Authority. He added that experts are thoroughly examining the information before making a decision. "We haven't achieved the desired outcome yet, but this is a step in the right direction."

Approximately 40,000 residents were ordered to evacuate from the surrounding area on 22/5 after the tank began leaking, releasing toxic fumes into the densely populated region. Orange County firefighters warned on 23/5 that the tank was heating up, raising concerns about a catastrophic explosion. They have continuously sprayed cooling water, hoping to reduce pressure in the tank and mitigate the risk of explosion.

Water being sprayed on the leaking chemical tank in Garden Grove, California, on 24/5. Photo: AP

MMA is a volatile and flammable liquid used in plastic production. The U.S. Environmental Protection Agency stated that MMA irritates skin, eyes, and mucous membranes, and can affect the respiratory and nervous systems with high or prolonged exposure. Orange County Health Director Regina Chinsio-Kwong said establishing a large containment zone around the tank was a necessary precaution.

As of 24/5, evacuated residents had not yet returned home, and several shelters were opened to provide temporary accommodation. Officials at the Disneyland resort, located about 8 km from the scene, said the venue "remains open to visitors" and they are closely monitoring the situation.