Ammonia (NH3) fumes from refrigeration were observed at 9 pm inside a dairy. The leak was located in the facility’s ice water tank. The presence of NH3 / NH4OH also caused strong odours at the level of the “standard” production lines, the thermostat devices of some machines (metering device) and the wastewater collection network. Masks were made available to technicians operating these lines between 8 am and 1 pm, by which time a complete rinsing of all sewers could be performed along with ventilation of the premises.

According to the operator, airborne NH3 concentration readings did not warrant alarm activation or employee evacuation. Subcontractors assigned installation maintenance undertook the necessary verifications to identify the causes of this incident and treat the NH3 leak; the pipe involved had been isolated and taken offline. A similar accident had already occurred on 5th February, 2009 (ARIA 37166). The introduction of a set of preventive measures was assessed before proceeding with equipment modifications (hydraulic and NH3 circuits, electric control boxes); the installation was placed back into operation on 15th March.