A potentially explosive chemical has formed in the exhaust ducts of a third-floor laboratory at the UCLA School of Public Health, and the building will be closed for one or more days during the week of Dec. 17 while workers remove the chemical, the dean of the school said Friday.
The chemical is perchloric acid crystals. Perchlorates can explode if they are shocked or exposed to heat or some chemicals.
“The chemical itself is not dangerous,” Abdelmonem A. Afifi, dean of the school, said in an interview. “Only when it receives a significant direct friction does it become dangerous.”
A company that specializes in the removal of hazardous chemicals will conduct a water wash to dissolve the crystals and to eliminate the hazard during the school’s Christmas holiday, Afifi said. An exhaust hood in the laboratory and roof ducting will also be removed.
The problem developed when the acid, a colorless, fuming liquid used in experiments, unexpectedly crystallized in the exhaust hood and the ducting system that vent the laboratory.
Officials have been aware of the potentially dangerous situation since February. At that time, “the laboratory was locked” and the ducting on the roof of the building was sealed, according to a memo Afifi sent to faculty, staff and students Friday. No other laboratories or ducting in the school were affected.
The memo added: “If the crystals remained and were significantly agitated by direct friction such as hammering or grating, there would be a slight risk of explosion.”
The public health school is housed in a seven-story building that forms the northern wing of the UCLA Medical Center complex in Westwood. It is connected through long hallways with other medical center buildings.
According to Afifi, the laboratory is used for “chemical experiments related to environmental health.” He said perchloric acid was “a normal chemical” used in the experiments.
The hazardous situation was discovered when officials received a request to replace the laboratory’s “worn out” exhaust hood, Afifi said.
After locking the lab and blocking access in February, Afifi said the school has been “in good shape safetywise.” Officials then consulted with Cal/OSHA, university safety officers and private industry about the best course of action. “Only this week did we finally have enough information to proceed,” he said.
The plan is to wash the exhaust ducts, which extend from the third floor to the roof, with water to dissolve the crystals “in a controlled fashion,” Afifi said. The water will then be collected and disposed of “in a safe manner.”
The details of the operation, including the number of days the school will be closed, are still being finalized.