Chemical Tank Fire Forces Evacuation of Schools, Neighborhood

A chemical tank exploded in flames Friday at a wood-processing plant in National City, forcing the evacuation of homes, businesses and 1,700 students and teachers at three schools.

No one was injured by the blast itself, fire officials said, but four National City policemen and a police cadet who were clearing the area and guiding traffic suffered minor throat irritation and chest pain. They were treated at nearby hospitals, National City Fire Marshal Patti Pittman said.

The 11:30 a.m. explosion and ensuing fire at the San Diego Wood Preserving Co. was set off by a welder working on a pipe that connected the 20,000-gallon storage tank with a cleaning tank, said Mary Avastu, spokeswoman for the San Diego County Department of Health Services’ hazardous materials division.

Oil or another flammable substance on the pipe caught fire, Avastu said, heating the wood-preserving solution in the storage tank and increasing pressure in the tank until it exploded, Avastu said. The roof of the two-story tank tower was blown from its bracings and hung to one side as flames and smoke poured out for about 90 minutes.

The welder was a safe distance from the tank when it exploded, Pittman said.

About 70 firefighters responded, Pittman said, and the fire was finally smothered with a chemical foam that was shipped in from four naval bases.

The neighborhood evacuation was ordered shortly before noon, with an announcement on the Emergency Broadcast System and with several dozen police and traffic officers patrolling neighboring blocks with their public address systems blaring.

Other persons within a 5-mile radius of the fire at 2010 Haffly Ave. were advised to remain inside their homes and to keep all windows and doors closed to limit exposure to potentially toxic smoke.

Nine hundred students from nearby John Otis and Kimball elementary schools were evacuated and taken to another school outside the immediate area. Another 780 students from National City Middle School were sent to Chula Vista High School to wait out the fire.

Students at another 10 schools in National City were advised to remain indoors until the smoke dissipated after 2 p.m.

Fire officials said the chemical tank, which was half full, contained a solution used to prevent wood from rotting. The solution is made up of about 93% water and smaller parts of arsenic, ammonia, copper and zinc, Avastu said.

Because of its high water base, Avastu said, the solution probably did not burn during the fire. Oil or carbon buildup on the tank lining probably fed the fire, she said.

“Very little solution was released into the area,” Avastu said.

Evacuations were conducted as a precaution, and there was no immediate evidence that area residents will encounter health problems because of the fire, said Bob Goggin, spokesman for the San Diego Air Pollution Control District.

Streets in a 12-by-6-block area near the waterfront--from Tidelands Avenue to National City Boulevard and 18th to 24th streets--were closed to traffic for about three hours while firefighters and hazardous-material crews contained the fire.

San Diego Wood Preserving Co. had recently been fined $42,000 for illegal storage and disposal of hazardous waste, according to a memo from the county district attorney’s office to the county’s Department of Environmental Health Services.

Since September, the company has been under order to rectify problems with storage, removal and record keeping. But inspection of the fire site after the blaze was quelled showed no apparent permit violations, Avastu said.

Calls to the company’s office Friday afternoon went unanswered.

“At this point, it doesn’t look like they were doing anything wrong,” she said. “Looks like they had an accident. That’s about it.”