WorkSafe Victoria recently issued a safety alert on the hazards and risks associated with automatic chemical dosing systems at swimming pools following an incident in which employees and swimming pool patrons were injured when a toxic gas was released into the pool area at an aquatic centre.
The incident occurred after an earlier electrical fault caused the automatic dosing system, used to administer chemicals to the pool water, to inadvertently mix sodium hypochlorite (pool chlorine) and hydrochloric acid (pool acid) together which resulted in a toxic chlorine gas.
The electrical fault caused the water filtering pump to shut down, resulting in no water flow within the pipeline. The pool chlorine and pool acid were automatically added into the pipeline that would normally return filtered water back into the swimming pool. Adequate water flow within the pipeline is necessary to prevent chlorine gas.
The safety alert recommended a number of ways to control risks: