This bachelor thesis focuses on the dangers and risks associated with leakage of hazardous chemical substance - ammonia. The first chapter defines the objectives of the work. The second part is devoted to the current state of the issue, safety data sheet for ammonia anhydrous, international ADR agreement. The third chapter deals with the characteristics of ammonia and its effects on man and the risks related to ammonia leakage. The fourth chapter is devoted to cases of ammonia leakage in Slovakia and abroad that took place in the past. The last chapter is devoted to the design of measures in the case of ammonia leakage in the selected plant OMNIA KLF, a. s. - the nitride workplace where ammonia is used in nitriding furnaces.