40,000 people under evacuation orders after a chemical tank leak in Southern California

About 40,000 people were under evacuation orders and schools shut down Friday in Southern California after a storage tank continued to leak a hazardous chemical used to make plastic parts that officials said could rupture or explode.

A storage tank holding between 22,700 and 26,500 litres of methyl methacrylate overheated 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.

Officials ordered residents in Garden Grove to leave and expanded evacuations orders 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.

''This is not precautionary. … This thing is going to fail, and we don't know when,'' said Garden Grove Fire Chief Craig Covey during a Friday afternoon press conference. ''We're doing our best to figure out when or how we can prevent it.''.

Covey said the tank could fail and crack, releasing the chemical onto the ground, or it could explode.

''We understand that this is frightening,'' Garden Grove Mayor Stephanie Klopfenstein said at the news conference. ''But the evacuation orders are in place for your safety.''.

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

He said the chemical is highly volatile, toxic and flammable.

''We are setting up these evacuations in preparation for these two options: it fails, or it blows up,'' Covey said earlier in a video update posted on social media. ''Please follow our requests and orders for evacuations.''.

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

No injuries or deaths have been reported, authorities said.

(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)