SWIMMING POOL DISINFECTANTS: SEASONAL USAGE AND STORAGE HAZARDS
BELLEVUE INCIDENT
On September 2, 1991, the Bellevue (NF.) Volunteer Fire Department was dispatched to a report of a fire and explosion at a residence with an aboveground swimming pool. En route the dispatcher informed first-due units that the homeowner was reporting a leak of chlorine gas from the swimming pool. The department’s haz-mat unit then was dispatched to the scene.
While en route, Fire Chief John Stacey requested weather information. Winds were from the southeast at 8 mph, temperature was 73°F, dewpoint was 70 percent, and relative humidity was 90 percent. The weather was relatively cool and cloudy for Labor Day weekend in Nebraska, but since changes in weather conditions are common there, 10-minute weather updates are standard and frequent requests.
Arriving units staged apparatus upwind. Residents of the home were evacuated from the incident area. Firefighters in full SCBA pulled two preconnect lines and charged them as a precaution. No lines were advanced — and no immediate action was taken —until more information was available. Responders questioned the homeown* er. There was no detectable odor of chlorine in the area.
Fortunately, the weather was unusually cool and dry. Intense humidity would have made the chlorine hug the ground, and strong wind would have spread the gas to neighbors. The cool weather dissipated the chlorine gas straight up into the air.
CHEMICALS DON’T MIX
The incident involved a 4‘/2-foot-deep aboveground swimming pool located adjacent to a deck attached to the house. The distance between the pool and the house was four feet. The pool’s owner had placed approximately six pounds of chlorine pellets into a floatable pool filter that already contained some pellets. What she didn’t realize was that she inadvertently mixed calcium hypochlorite pellets with chlorinated isocyanurate pellets—two types of chemicals used to disinfect swimming pool water, which are incompatible. The filter, being a closed system of sorts, allowed heat to build up and the two chemicals to mix. A violent chemical reaction ensued, causing the filter to explode and scorch the deck. Since the homeowner already had placed the filter in the pool when the reaction occurred, the pool water prevented a structure fire.
Responders immediately placed a call to CHEMTREC, who in turn notified the product manufacturer, Olin. Per din’s instruc tions, firefighters in full turnout gear, including gloves, full respiratory protection (SCBA), and sleeves and cuffs taped down with duct tape, took the filter out of the pool, placed it in a garbage can partially filled with water and sitting in the sun, and poured water on the filter to neutralize the remaining pellets. The sun and water were the neutralizing factors. Firefighters used an attack line off the engine to agitate the water in the pool and dissipate any remaining pellets there.
Following mitigation, responders tested the garbage can and pool with pH strips and found them both to be within tolerance. They declared the incident under control one hour and two minutes after the initial alarm.
On-site decon with water was performed on responders, and the incident concluded.
