The present invention relates to new fluoroketone compounds from the groups monobromoperfluoroketones, monohydromonobromoperfluoroketones, (perfluoroalkoxy)monobromoperfluoroketones, (fluoroalkoxy)monobromoperfluoroketones, and monochloromonobromoperfluoroketones. These fluoroketone compounds have utility in preventing, controlling and extinguishing fire. These fluoroketone compounds have further utility as additives to reduce or eliminate the flammability of normally flammable working fluids such as refrigerants, foam blowing agents, solvents, aerosol propellants, and sterilants.