How will Orange County’s chemical problem be solved? Here’s what we know

The battle to keep the highly toxic chemical from exploding took a step back on Saturday.

The temperature in a failing tank filled with a highly toxic and explosive chemical in Orange County is rising, not falling, officials said.

On Saturday morning, the temperature in the pressurized tank at the airport in Garden Grove was 90 degrees, down from 77 degrees the day before. Temperatures are rising about a degree per hour, Craig Covey, chief of the Orange County Fire Authority, said Saturday morning.

But with the chemical crisis in its third day, the new information offers more insight into how it might be resolved, though no one is sure when.

The question, experts say, is whether officials can deal with these dangerous chemicals in a way that doesn’t end in an explosion or the kind of spill that causes environmental destruction.

Trying to cool the damaged tank

An increase in temperature raises the risk of explosion.

The boiling point of the chemical inside the tank, methyl methacrylate, is 101 degrees Celsius. The temperature gauge in the tank only detects temperatures up to 100 degrees. Officials have not disclosed what temperature they would consider an eruption imminent.

It’s unlikely that a tank will explode at 101 degrees, said Elias Picazo, an assistant professor of chemistry at USC.

“It depends on the integrity of the tank, the shape of the tank, and the pressure of the tank,” said Picazo. “But, yes, above 100, the pressure starts to increase significantly, because the liquid phase becomes the gas phase, and the gas takes up any available space. It will take up more volume and have more pressure.”

What does it mean that the temperature is rising?

The fact is that the temperature in the tank indicates that the molecules of liquid MMA – monomers, in fact a number of single molecules – react to form polymers, to form a solid, according to Picazo. “The reaction is to release heat. That will start more reactions, so it can break.”

The biggest fear is producing what are known as “thermal runaway reactions.”

Covey said that if the temperature in the tank exceeds a certain threshold “we know the tank is going to go into a hot zone, and we’re going to get everyone out of the area, make sure it’s safe, and let the tank do what it’s going to do.”

The fact that some liquid in the tank reacts to solidification is probably what happened when the valve to the tank was blown. The main solution to solve this problem would be to pump a catalyst into the problem tank, to extinguish it and prevent it from exploding.

But that valve is closed, so there is no way to get the neutralizing agent inside the tank. And there is no way to slowly drain the toxic chemical tank of MMA.

Keeping the tank as cool as possible can be a practical way to prevent explosions.

How do officials play situations?

There is still a chance that the tank will explode or explode in the event of a major leak that could send the chemical into rivers and oceans. Officials have marked a large evacuation zone – anywhere from 1 to 3 miles from the tank – affecting an estimated 40,000 residents that includes parts of the cities of Garden Grove, Anaheim, Buena Park, Cypress, Stanton and Westminster.

It is clear that spraying the water in the tank helps.

Even though the temperature was rising inside the tank, not putting cool water in it would have allowed the temperature inside the tank to rise too quickly, Picazo said.

So the big solution right now is for the crew to do their best to keep the tank as cool as possible – and buy time.

Keeping the tank cool can prevent an explosion

Continuing to pour cool water into the tank can allow the liquid chemical inside to cure more slowly — solidify at a slower rate — and reduce the pressure build-up inside the tank, Covey said.

“It’s like an ice cube that’s cold on the outside – this thing is healing, it’s heating and it’s healing on the outside. While it’s doing that process, it’s building that pressure,” Covey said.

A tank has the capacity to hold a certain pressure. There is an empty space between the top level of the MMA chemical to the roof of the tank.

“We’re hoping that space can absorb the healing rate slowly and not overpressurize and explode,” Covey said.

In other words, continuing to cool the tank may slow down the chemical reactions taking place inside in a way that prevents an explosion.

Picazo agreed.

“One of the best conditions is to allow the [MMA] the monomers react, but you do it in a controlled way,” he said.

“Perhaps if it’s slow enough, you can build up a viscosity inside the tank and cause the monomers, the active monomers, to separate.

“If they don’t communicate, they can’t react,” said Picazo. “You need contact to reactivate, and you can’t contact when you’re in a stable condition.

At that point, “then you can start thinking about other solutions for how to delete the first unanswered item.”

Can the worst case scenario be prevented?

Firefighters said they hoped to contain the explosion.

“We’re hopeful,” Covey said. “We bring people from all over the country, we talk to people everywhere, we try to come up with more ways.

“Letting this thing fail and explode is unacceptable to us.”

What makes the workers mistakenly think that the temperature is cooling inside the tank

Officials on Friday thought the water spray was actually cooling the problem tank – not just slowing the rate at which the temperature was rising.

On Friday evening, Picazo said thermometers showed the tank was 61 degrees, and the goal was to get the tank down to 50 degrees, which would be a “happy place.”

But as it turns out, the drone’s thermometers were detecting temperatures outside the problem tank, not inside it.

Officials discovered the error of their ways when a crew returned at night to the problem tank, which had about 7,000 liters of MMA in it. Next to the problem tank is a second tank, which has 15,000 liters of chemicals in it, but is in no danger of immediate failure.

However, officials wanted to inject a depressant into that second tank, so that if the failed tank exploded, it wouldn’t cause an even bigger explosion by igniting the second tank. So there was an all-night operation by pharmacists and first responders who were sent to try to do that, even though it put them “at risk,” Covey said.

When they arrived, they were also able to manually read the tank’s internal temperature gauge that was failing. (That gauge is invisible unless someone is reading it; it’s covered in water-cooling spray and can’t be seen from a distance, or by placing a drone with a camera next to it, Covey said.)

That’s when the crew realized that the temperature inside the tank was 90 degrees, and that relying on drones to measure the temperature remotely only showed the temperature outside the tank, not inside.

Staff writers Hailey Branson-Potts, Hannah Fry and Eric Licas contributed to this report.