KABC, CNN
By Nina Giraldo, Taylor Romine, Emma Tucker, Alaa Elassar, CNN
(CNN) — Firefighters have found a potential crack in a massive tank filled with a toxic chemical that may be relieving pressure inside, a development an official described as a step in the right direction.
If the discovery is confirmed, it could alter the response strategy and possibly scale back the evacuation area as crews work to prevent a potentially catastrophic explosion in Southern California.
About 50,000 people in Orange County remain under an evacuation order as of Sunday, with many spending the Memorial Day weekend in shelters, hotels or with friends and family outside the danger zone. Busy tourist destinations like Disneyland and Knott’s Berry Farm are nearby but are not included in the evacuation zone.
The chemical inside the tank, methyl methacrylate, or MMA, can cause respiratory issues and irritation to the skin and eyes upon exposure, according to the Environmental Protection Agency.
“Our firefighters went in, and they were able to visualize the tank. What they found was a potential crack in the tank, which could potentially be relieving some of the pressure in there,” Orange County Fire Authority Interim Fire Chief TJ McGovern said Sunday.
McGovern said the discovery was “a step in the right direction” and asked the public for their patience.
McGovern told CNN there is currently no leak or impact on air quality, adding that continuous air monitoring at the scene has shown readings remain within normal limits and nothing is currently escaping from the tank.
The tank’s temperature gauge has maxed out at 100 degrees, making it difficult to determine how much hotter conditions inside may actually be, McGovern said.
“A low-volume release, where the local authorities are going to be able to monitor, neutralize, and contain a threat,” is most likely, Environmental Protection Agency Administrator Lee Zeldin told CNN earlier Sunday morning.
Here’s what we know about the tank and what authorities are doing to prevent a potential disaster:
Tank began to overheat Thursday
Authorities first responded to GKN Aerospace in Garden Grove on Thursday for a vapor release from the tank, McGovern said Friday. One of the tanks at the facility had overheated and activated a relief valve and sprinklers to cool the tank, he said.
But the valves on the tank were “gummed up” and the temperature inside has continued to rise, reaching as high as 90 degrees, officials have said. Methyl methacrylate’s “happy place” is 50 degrees, Orange County Fire Authority Division Chief and Unified Incident Commander Craig Covey said Friday, noting the increase in temperature could lead to a leak or explosion.
“Right now, this is an emergency response. This isn’t yet an environmental response, and the scale of that environmental response will be determined based off of what happens when that tank fails,” Zeldin said Sunday.
Authorities were attempting Saturday to solidify the chemical inside the tank from