A failing tank in Garden Grove holding toxic chemicals has prompted major evacuations covering six Orange County cities, and officials are not sure when the orders will be lifted.

The evacuation perimeter stretches from Ball Road to the north, Trask Avenue to the south, Valley View Street to the west and Dale Avenue to the east. That includes parts of Garden Grove, Cypress, Stanton, Anaheim, Buena Park and Westminster.

Beach Boulevard is closed from Garden Grove Boulevard to Orangewood Avenue. Several off-ramps are closed on the 22 Freeway including Beach Boulevard, Knott Avenue and Valley View Street.

• Barker Elementary School

• Bryant Elementary School

• Carver Elementary School

• Enders Elementary School

• Garden Park Elementary School

• Lawrence Elementary School

• Wakeham Elementary School

• Patton Elementary School

• Bell Intermediate School

• Alamitos Intermediate School

• Pacifica High School

• Rancho Alamitos High School

• Skylark Preschool

• Garden Grove Unified’s maintenance and operations facility

• Lampson Bus Yard

• Garden Grove: 13641 Deodara Drive

• Cypress: 5700 Orange Ave.

• Fountain Valley: 16801 Euclid Street

• Anaheim: Savanna High School, 301 N. Gilbert Street

The Orange County Fire Authority initially responded to reports of a hazardous materials incident at a business in the 12000 block of Western Avenue at 3:30 p.m. Thursday, officials said. Upon arriving at the scene, officials determined that methyl methacrylate, a volatile liquid used to make plastic, was leaking out of a 34,000-gallon vat.

Crews worked overnight hoping to mitigate the leak, said OCFA Chief TJ McGovern, but whatever progress was made going into Friday morning, ultimately was not enough.

“We have a tank that is actively in crisis, for lack of a better word,” Incident Commander Craig Covey said. “The tank that is in the biggest crisis is, in fact, unable to be secured and mitigated.”

In a statement posted on Facebook on Friday morning, Garden Grove Mayor Stephanie Klopfenstein said crews had a setback when the valve to one tank became frozen and pumps were affected because of water that was being poured on the tanks to keep them cool.