All evacuation orders lifted, no threat of explosion, fire or leak at Garden Grove chemical tank

The toxic chemical inside the large storage tank that was leaking in Garden Grove is methyl methacrylate, or MMA.

It is a highly volatile and flammable chemical that, according to the Environmental Protection Agency, is used to make resins and plastics.

Doctors say the chemical can irritate the skin and eyes.

Short-term exposure - such as inhalation - can cause significant irritation of the lungs and nasal passages. It can also lead to nausea and dizziness.

More severe effects are also possible.

"At very high levels, it can really cause severe respiratory distress and hospitalization and this is where we really need everybody to heed all the evacuation orders," said Orange County Deputy Health Officer Dr. Regina Chinsio-Kwong.

What can exposure to methyl methacrylate, MMA, do to humans? The toxic chemical was leaking from a tank in Garden Grove.

As for long-term effects, doctors say it may impact other organs.

The chemical can also affect birds and other animals, though the effects may vary by species.

First responders are also taking into account the potential for a hazardous plume.

Officials said they are actively monitoring air quality and, as of early Friday afternoon, levels were within normal limits.

Authorities are calling a toxic chemical leak in Garden Grove a "crisis situation," triggering evacuation orders for roughly 40,000 residents and school closures.

The tank at GKN Aerospace is carrying a highly toxic and flammable chemical used to make plastics. Now, fire crews say the tank is going to fail in one of two ways: either with a spill of thousands of gallons of toxic chemicals or an explosion. Authorities just don't know when or how it will end.

"There are literally two options left remaining," Orange County Fire Authority (OCFA) Division Chief Craig Covey said. "One, the tank fails and spills a total of about 6,000 to 7,000 gallons of very bad chemicals into the parking lot in that area, or two, the tank goes into a thermal runaway and blows up, affecting the tanks that are around them that have fuel or the chemicals in them as well."

Covey stressed that "there is no active gas leak, no plume in the area," but he warned residents to heed the evacuation warnings and remain out of the area due to the possible spill or explosion. Officials said air quality was being actively monitored in the area, and all readings were still within healthy limits.

Fire crews say the chemical spill is the better outcome because they have set up a containment barrier around the tank to prevent the material from entering storm drains, river channels or reaching the ocean. Still, there's no telling what will happen.

Covey said a spill of the chemical is actually the "best-case scenario and, believe it or not," favorable to an explosion and a possible plume of toxic material spreading over the area.

City News Service contributed to this report.

Orange County Fire Authority crews and Garden Grove police initially responded around 3:30 p.m. Thursday to GKN Aerospace at 12122 Western Ave. due to a chemical that became overheated inside a 34,000-gallon tank containing a toxic chemical used in plastic manufacturing, causing the tank to begin venting vapors and triggering a sprinkler system designed to spray water on the tank to cool the material inside. The tank is located in proximity to two other storage tanks.

Evacuation orders were initially issued on Thursday, but they were lifted Thursday night when crews believed they were making progress in mitigating the situation. But Friday morning, the orders were re-instituted "due to changing conditions," according to the OCFA.

As the morning wore on, the situation worsened, preventing mitigation efforts completely, and the evacuation zone was expanded to create a roughly one-mile buffer area around the tank.

OCFA Division Chief Craig Covey said told reporters he went home Thursday night feeling authorities were making significant progress controlling the situation, but then he received a call at 4 a.m. reporting the situation had worsened. The main issue was a faulty valve on the compromised tank, which prevented crews from being able to access or offload the chemicals inside. Crews were also unable to introduce a stabilizer to neutralize the material.

By later Friday morning, authorities said one of two options is imminent: the 7,000 gallons of toxic chemicals inside the tank leak out, or the tank blows up.

City News Service contributed to this report.

The Garden Grove Unified School District announced that classes were canceled until further notice at the following campuses due to a chemical leak at GKN Aerospace:

• Barker Elementary School
• Bryant
• Carver
• Enders Elementary School
• Garden Park
• Lawrence Elementary School
• Wakeham Elementary School
• Patton Elementary School
• Bell Intermediate School
• Alamitos Intermediate
• Pacifica High School
• Rancho Alamitos High School
• Skylark Preschool
• Maintenance and Operations Facility
• Lampson Bus Yard

City News Service contributed to this report.