Abstract: On June 28, 2006, anhydrous ammonia was released from a pressure relief valve on the F3 Kathabar dehumidifier and refrigeration unit. The anhydrous ammonia was piped from the pressure relief valve to the roof where it was released. The anhydrous ammonia collected outside of the building housing the F3 Kathabar unit, in the B & C Fermentation Tank Corridor. Employee #1 was exposed to the anhydrous ammonia when he entered the B & C Fermentation Tank Corridor to check a carbon dioxide sensor. Upon entering the corridor, Employee #1 noticed a strong smell of ammonia and experienced burning and watery eyes and difficult breathing. Employee #1 exited the corridor and was taken to the hospital for observation and minor treatment, but he was not hospitalized.