Firefighters have found a potential crack inside a damaged chemical tank in Southern California that may help relieve pressure and possibly reduce the risk of a violent explosion, a fire official said on May 24.

California Gov. Gavin Newsom earlier declared a state of emergency in Orange County after the damaged tank was determined to be at risk of exploding or spilling thousands of gallons of toxic material. Authorities have ordered 50,000 residents in the area to evacuate.

TJ ​McGovern, interim fire chief of the Orange County Fire Authority, said in a video message posted on X that firefighters carried out a “recon mission on the tank” overnight.

“During that operation, 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,” he said.

McGovern said the possible crack was “positive intel” and that officials are vetting and validating the discovery. He also noted that a specialized team has been formed to deal with the situation.

“With this new information, it could change our trajectory and our strategy to this event,” he said. “We’re not there yet, but this was a step in a right direction and there’s going to be a lot more coming shortly.”

The Orange County Fire Authority said in a subsequent update on X that an evacuation zone has been established and that “any areas outside of this zone are currently considered completely safe and day-to-day activities can continue as normal.”

The malfunctioning tank, which is located at GKN Aerospace, carries thousands of gallons of methyl methacrylate, a flammable and volatile chemical used in plastics manufacturing for aerospace applications.

Exposure to methyl methacrylate can cause serious respiratory problems, including lung irritation, health officials said. Higher-level exposure can cause fluid to increase in the lungs, with severe shortness of breath, dizziness, irritability, and problems with concentration and memory.

Lee Zeldin, administrator of the Environmental Protection Administration (EPA), told CNN on May 24 that the most likely scenario is a “low-volume release” of the tank, where officials will be able to “monitor, neutralize, and contain the threat.”

“We’re being told that the tank will fail, but there are different scenarios as to what that means, the most catastrophic scenario being an explosion that results in other tanks to explode. That’s the reason why you see such a big evacuation that’s been done in the surrounding areas,” he said.

Firefighters have been spraying water on the exterior of the tank to keep temperatures down and help prevent an explosion.

Orange County Fire Authority Division Chief Craig Covey said on May 24 that drones were monitoring every 10 minutes to watch for any temperature spikes and that officials were also preparing measures to prevent a possible leak from spreading into waterways or the ocean.

Jack Phillips and Kimberly Hayek contributed to this report.