Authorities in southern California are racing to figure out how to prevent the explosion of a storage tank that has been leaking a hazardous chemical used to make plastic parts, as some 40,000 people were under evacuation orders in the area.

A storage tank holding between 22,700 and 26,500 litres of methyl methacrylate overheated on Thursday and began venting vapours into the air at an aerospace plastics facility in Garden Grove, a city in Orange County, the county’s fire authority said on Friday. The tank could fail and crack, releasing the chemical onto the ground, or it could explode, city fire chief Craig Covey said.

“This thing is going to fail, and we don’t know when,” Covey said. “We’re doing our best to figure out when or how we can prevent it.”

Officials ordered residents in Garden Grove to leave and expanded evacuation orders on Friday to some residents of five other Orange County cities – Cypress, Stanton, Anaheim, Buena Park and Westminster – after being unable to stop the leak overnight on the tank at GKN Aerospace, which makes parts for commercial and military aircraft.

In an update later on Friday, Covey said authorities have been able to maintain the tank's temperature, buying time to figure out how to fix it.

Garden Grove is about 61 kilometres south of downtown Los Angeles and less than 1.6 kilometres from Disneyland's two theme parks, which were not under the evacuation orders. The city is known for its vibrant Vietnamese community, one of the largest of any US city.

Covey said crews have created containment barriers with sandbags in case there is a chemical spill from the tank to prevent the toxic chemical from getting into storm drains or reaching creeks or the nearby ocean.

Dr Regina Chinsio-Kwong, the county health officer, said if the chemical heats up, it can release a vapour that is harmful to people’s health. It can cause respiratory issues, itching and burning eyes, nausea and headaches.

Crews were initially successful and were able to neutralise one of two damaged tanks, but Covey said they determined on Friday morning that the remaining tank was “in the biggest crisis”.

GKN Aerospace said specialized hazardous material teams are assessing the situation. (AP)



Edited by Azam Khan