An “unprecedented” situation was raging in Orange County on Friday, as a chemical tank at an airline threatened to explode and release a highly toxic chemical that could cause severe respiratory distress and lead to hospitalization, officials said.
An estimated 40,000 residents were asked to evacuate, disrupting parts of the cities of Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster. Disneyland is outside the exit.
“This is highly volatile, highly toxic, highly flammable,” said Craig Covey, Orange County Fire Authority chief and incident commander. Officials said they do not remember a similar situation happening before.
So what is the science of leaks and why do officials say it's so dangerous?
What's going on?
Three large tanks containing a highly toxic chemical called methyl methacrylate, or MMA, used to make plastic, are at issue near the 12000 block of Western Avenue in Garden Grove.
One of the most vulnerable and problematic tanks has about 7,000 gallons of chemicals left in it, Covey said.
There are two options for what will happen in the tank, said Covey, who first felt the temperature rise on Thursday.
“The first one, it fails and cracks, and all the product seeps down,” Covey said, and efforts are underway to try to prevent the liquid “from going into storm drains and into our rivers and oceans.”
That is a very good situation, because if it leaks, we are no longer in danger of exploding. From there, teams wearing hazmat suits can go in and “reduce and reduce the vapor that's going to be coming off that.”
The worst case scenario is an uncontrolled explosion. “If you've ever seen the videos of tank cars on railroad tracks exploding, and the fireball going off, then blowing up half a tank car half a mile down the railroad tracks, that's the potential scenario we're facing if this is a catastrophic failure,” Covey said.
These were the options: “a leaky tank or an exploding tank,” Covey said at a Friday afternoon briefing. “This is going to happen unless the other guy behind me here figures out how to slow this down. This thing is going to fail. We don't know when.”
The incident occurred at GKN Aerospace, which manufactures engine structures, landing gear and other products for commercial and military aircraft.
What are the health risks of explosions?
MMA is very toxic. Short-term exposure that involves inhaling chemical vapors “can cause severe irritation to the lungs, nose, and can cause nausea and dizziness,” said Dr. Regina Chinsio-Kwong, Orange County health officer.
At very high levels of exposure, “it can cause severe respiratory distress and hospitalization,” Chinsio-Kwong said.
Emissions are large in part because of the potential of toxic waste.
Officials said the chemical is heavier than air, so it will settle and sink to the bottom of the facility in the event of an explosion. Officials are assessing the risk of chemical emissions in other areas.
Methyl methacrylate can easily evaporate and settle near the ground as a hazardous vapor, according to the US Environmental Protection Agency. If inhaled at high levels, this smoke can irritate a person's lungs, causing coughing, wheezing and chest tightness. It can also cause nausea, dizziness and itching of the skin.
Although the EPA has classified the chemical as “not likely” to be carcinogenic to humans, long-term exposure has been linked to severe organ damage.
Why can't the officials safely remove the toxic chemical from the tank, without leaking or exploding?
Of the three tanks containing toxic chemicals, crews were able to inject a chemical into one tank to reduce its volatility, Covey said. They couldn't do that with the second tank, but it's not in critical condition.
But the tank in the worst case has broken valves and is “stuffed,” so the reinforcing chemical can't be added to the explosive chemicals, Covey said.
The broken valves also meant crews couldn't remove the burst chemical tank, according to Orange County Fire Authority Chief Nick Freeman.
“We couldn't get anything out, and we couldn't find anything to stabilize these things,” Freeman said.
Officials are trying to see if there are other ways to resolve the situation without a spill or explosion.
“We put together a team to think outside the box… [we] they're calling people across the state and across the country to come together with ideas on how we can safely get in there and depressurize the pressurized tank and minimize the exposure it has,” Covey said.
The state of emergency began to emerge on Thursday, when one of the three tanks began to experience an increase in temperature. A relief valve was activated and an overhead sprinkler system was turned on to cool the chemical, Orange County Fire Authority interim chief TJ McGovern said.
The tank in critical condition was already exploding on Thursday. “It's gotten to the point where it's doing what we call a BLEVE, which is a 'boiling liquid expanding vapor explosion,'” Covey said.
Officials initially had success cooling the tanks using sprinklers, Covey said, but the situation took a turn for the worse on Friday when they discovered they couldn't remove the coolant from the tank that wasn't working because the valves were broken and gummed up.
Is there a chemical leak currently active?
As of Friday afternoon, there were no toxic chemicals leaking from the tank.
“We've cooled it enough. That purge valve on it doesn't purge any kind of product,” Covey said. “There's nothing in the air right now.”
One of the tanks on Thursday released steam after the tank overheated. As a result, the relief valve was activated, and the tank was cooled with an overhead sprinkler system.
Will officials know in advance when an explosion will occur?
Drones monitor the temperature in the tank, Covey said.
“We also have a set temperature where, when it gets to that point, we know the tank is going to go into the hot zone, and we're going to get everybody out of the area, make sure it's safe, and let the tank do what it's going to do,” Covey said.
Are people cooperating with exit directions?
Garden Grove Police Chief Amir El-Farra said most people do come out, but about 15% refuse to come out.
Can the discharge last for days?
“I don't have an answer for you on that,” El-Farra said.
How big is the outlet?
The outlet is approximately one to three miles from the failing chemical tank, located northeast of the corner of Western and Lampson avenues.
What's next to a chemical tank failure?
There are residences less than 400 feet east of the failing chemical tank in the town of Stanton.
Are people exiting outside the exit?
The Orange County Superior Court has recommended that non-essential workers leave the courthouse in Westminster, which is outside the evacuation zone.
