The Montreal Protocol on substances that deplete the ozone layer is an international treaty designed to protect the ozone layer by phasing out the use of a number of substances responsible for ozone depletion. The protocol was adopted in 1987 and covers among other substances, HCFC-22 used as refrigerants. The Canadian governments (federal and provincials) have put in place legislations to phase out and prohibit the use, production, and importation of HCFC-22 substances and equipment using HCFC-22 as refrigerant. Refrigeration systems are used in over 500 hockey arenas in the province of Quebec and 400 of them have to be modified to use a more ozone friendly refrigerant, that is, ammonia. Therefore, the risk associated with these sites is a major concern for the population due to their close proximity. The article presents approaches that are used to reduce the risk to an acceptable level for the neighbors and users. (c) 2013 American Institute of Chemical Engineers Process Saf Prog 32: 7883, 2013