A worker was exposed to NH3 while working next to a live refrigeration unit. The worker was working from an elevating work platform (EWP) to install a partition wall in a large refrigerated space. The EWP was in close proximity to a chiller unit that was operating during the work. The EWP knocked a valve on the chiller unit, releasing high-pressure ammonia refrigerant. The worker was sprayed in the face with ammonia and inhaled ammonia, causing severe lung inflammation and burns to the respiratory tract, requiring treatment in an intensive care unit. The incident had the potential to cause fatal injuries. The incident also resulted in failure of the refrigeration system and the loss of a large amount of high-value food.