About 16,000 Californians are still out of their homes because of an overheated chemical tank
About 16,000 people remain under evacuation orders in Southern California as an overheated chemical tank continues to pose a threat to nearby homes, and officials did not say Tuesday when residents would be able to return home.
The crisis forced 50,000 people to evacuate areas near the Orange County city of Garden Grove last week. An accidental rupture in the tank relieved the pressure and helped avert a catastrophic explosion, allowing many evacuees to return home over the US Memorial Day weekend.
But the risk of a small explosion or possible spill kept orders in place for about a third of those who left. Many are living outside of hotels, tents, emergency shelters at schools or staying with family or friends.
Isabel Mendez was among those still waiting to return to her cell phone. He said a bump appeared on his face and he bit his lips and his throat hurt when he went out last week. After spending several expensive nights in a hotel, he now lives with his mother in the Los Angeles area.
Mendez said he is not sure about returning home because he does not trust official guarantees that the area is safe. “It’s definitely still dangerous,” he said.
Exposure to methyl methacrylate – a highly flammable chemical used to make plastics – can cause serious respiratory and neurological problems, as well as irritation to the skin, eyes and throat, according to the federal Environmental Protection Agency (EPA).
The tank for GKN Aerospace Transparency Systems, which makes cockpit windows, canopies and windshields, contains between 22,700 and 26,500 liters of chemicals.
“We apologize for the ongoing disruption caused by this incident, and the priority remains a safe solution,” the company said, “so that residents can return to their homes as quickly as possible.”
Separately, a chemical tank explosion Tuesday at a paper mill in Washington state killed one person and left nine others unaccounted for, authorities said.
Fire officials say a possible rupture in a pressure tank containing a toxic and highly flammable chemical at an aerospace manufacturing facility in California could help avert a catastrophic explosion as tens of thousands of residents were ordered to evacuate.
Cooling system valve failed
Crews at the California plant worked through the night to ensure two nearby tanks were inoperable and would not be affected by the damaged tank, said Orange County Fire Captain Brian Yau.
The tank overheated because a valve in the cooling system failed, fire officials said.
“That’s what ended up at 50 degrees,” or 10 C, said Orange County Fire Authority Division Chief Craig Covey.
“As a result of that failure, the tank went into the heating system because it did not continue to cool,” he said at a press conference on Monday evening.
Crews sprayed water in the tank until the internal temperature stabilized at 33.3 C, down from 37.7 C at the weekend, firefighters said on Tuesday.
The plant’s sprinkler system continues to empty the tank, and the company said its technicians and firefighters removed the material from the tank to cool it.
Fire officials also tested the flood water and found it to be clean, McGovern said.
“There was no contamination,” Orange County health director Regina Chinsio-Kwong said at a Monday news conference. “You should feel comfortable going home even if you’re across the street on that new property line.”
Natural hazards
The crisis took place in central Orange County, a densely populated area made up of a cluster of cities, including Garden Grove. The city of 170,000 people, along with neighboring Westminster, is home to Little Saigon, the largest Vietnamese community outside of Vietnam.
It’s also near Anaheim, home to two Disneyland theme parks, which were not under evacuation orders.
The South Coast Air Quality Management District will monitor the air for several months, and the EPA will be checking sewers and storm drains for leaks, said Orange County Supervisor Janet Nguyen.
As the tank heated, the chemical changed from a liquid to a gas, increasing the pressure and risk of explosion, said Andrew Whelton, a Purdue University engineering professor who has studied environmental pollution. Some of the methyl methacrylate may have already hardened into a stable plastic like plexiglass, reducing the risk, he said.
“The tank was on its way to a catastrophic explosion,” Whelton said. “The formation of the crack seems to allow pressure to escape.”
The risk remains of a small explosion that could send projectiles or a chemical plume into nearby homes, he said, adding that the tank needs to approach 15.6 C to 21.1 C before conditions are considered too safe.
The California crisis is reminiscent of the 2014 chemical spill in Charleston, W.Va., caused when storage tanks failed. The spill prevented the capital and surrounding areas from using tap water for several days.
Businesses were temporarily closed and hundreds of people headed to emergency rooms to deal with problems ranging from nausea to vomiting. The disaster prompted a new state law requiring more inspection and registration of above-ground tanks.
