May 25 (UPI) — A malfunctioning 37,000-gallon tank holding toxic chemicals in Orange County, Calif., no longer poses a threat for a catastrophic explosion, local fire officials said Monday.

Nearly 50,000 Orange County residents in and around Garden Grove, Calif., have been evacuated since Friday due to a threat of an explosion at the GKN Aerospace facility, located about 33 miles southeast of downtown Los Angeles.

The overheated tank holds methyl methacrylate, or MMA, a flammable, toxic and highly volatile substance used in the production of acrylic plastics.

But after officials reported seeing a pressure-relieving crack develop in the tank on Sunday, 24 hours later they announced the possibility of destructive blast was over.

“We are happy to report that the threat of a [catastrophic explosion] is now off table,” Orange County Fire Authority Interim Chief T.J. McGovern said in a video update. “That threat has been eliminated.”

OCFA Division Chief Craig Covey said firefighters sent into the exclusion zone over the weekend were able to confirm their earlier findings that a crack has relieved pressure inside the tank.

“The crack is there, we have verified that it’s there, and the tank he released its pressure,” he said.

Covey also confirmed that efforts by firefighters to cool the tank by continually dousing it with water have been successful.

“The temperature has been stabilized and is actually reducing,” he said. “It is currently 93 degrees, down from 100 degrees. That is incredibly positive news as we turn the corner on this incident.”

Area residents remained under mandatory evacuation orders on Monday as an interagency response team warily eyed the malfunctioning tank holding MMA, a flammable, toxic and highly volatile substance used in the production of acrylic plastics.

They were evacuated Friday after a chemical vapor leak was spotted coming from the tank, which has a malfunctioning valve and is unable to be neutralized. Officials say the valve has seized due to a chemical reaction with the MMA.

Although the worst-case scenario of a catastrophic blast causing mass damage has been taken off the table, there are still elements of danger in the situation, officials cautioned.

The possibility of a smaller explosion releasing chemicals and debris from the plant still exists, as does the possibility of a wind-borne chemical plume developing following the release of liquid MMA onto the ground.

Because of that, the evacuation orders remain in place, McKenna reiterated.

“We want to be clear — the evacuation zones are still in play,” he said. “Please abide by those evacuation zones.”