By Taylor Romine, CNN
(CNN) — Approximately 40,000 residents in Orange County, California, are under evacuation orders as authorities are concerned a tank filled with a toxic chemical will either leak or explode.
Authorities have spent the past two days trying to prevent the tank full of the chemical methyl methacrylate from exploding after it began to overheat. They had issued evacuation orders to the 9-square-mile area around the facility involved, impacting over 40,000 residents.
The chemical, also known as MMA, is used to manufacture plastics and can potentially cause respiratory issues if humans are exposed, according to the Environmental Protection Agency.
On Friday, police made a reverse 911 call to tell people to evacuate and posted on social media about the evacuations, Garden Grove Police Chief Amir El-Farra said. About 15% of people — or about 6,000 residents — from the evacuation order area had refused to leave, he said.
The industrial site where the tank is located is about 5 miles from Disneyland and about 4 miles from Knott’s Berry Theme Park. MMA is heavier than air, OCFA Division Chief and Unified Incident Commander Craig Covey said at the news conference Friday, but it’s not immediately clear how wind patterns could impact the spread if there’s an explosion.
“This is going to happen unless some brilliant guy behind me here figures out how we can mitigate this incident,” Covey said as he emphasized the need to evacuate. “This thing is going to fail.”
Exposure to MMA can cause major respiratory issues, including “significant irritation” to the lungs and nasal passages, as well as dizziness and nausea, Orange County Health Officer Dr. Regina Chinsio-Kwong said. There are not many documented cases of human interaction, so it is unpredictable what the effects of a potential explosion could be on the population, she said, encouraging people to stay out of the evacuation zone for that reason.
“We’re going into unique times and we have limited information,” Chinsio-Kwong said.
Authorities initially responded to a vapor release from the tank containing MMA at the Garden Grove facility on Thursday, Orange County Fire Authority Interim Fire Chief TJ McGovern said Friday. One of the three tanks at the site had increased in temperature and activated a relief valve and overhead sprinklers to try to cool the tank, he said. The other two tanks have either been neutralized with a chemical agent or aren’t at risk.
Evacuation orders were issued for the area Thursday, but they were lifted that night after the vapor conditions improved, McGovern said. As crews tried to remove and contain the product from the one tank, they realized the tank had a damaged valve so the chemical couldn’t be removed, which caused local authorities to reinstate the evacuation orders, he said.
McGovern emphasized that there was no vapor coming out of the tank as of Friday, and authorities are continuing to monitor the air quality.
The manufacturer’s response team had tried everything they could but couldn’t mitigate the crisis, Covey said Friday. The only two options given to authorities were either the tank would crack and leak the 7,000 gallons of MMA into the surrounding parking lot, or the container would explode, he said. CNN has reached out to GKN Aerospace Transparency, the owner of the facility, for information on their efforts to manage the emergency.
“This is highly volatile, it’s highly toxic and it’s highly flammable,” Covey said.
Authorities warned that there were many factors that could contribute to the tank’s demise, which is why they expanded the evacuation orders to such a large area. “People need to get out of their houses and get into a safe space because when this thing goes, depending on the wind