thanks for the correction, but as far as refrigerators go, the absorption refrigeration cycle isn't as energy efficient as the compressor type of cooling systems, when used with electricity.
the units require a vent to the outside when used with a gas or oil flame. the cost of the gas line and vent keeps the units from being used in main stream housing. they are still used in all r. v. 's and remote locations. most large commercial cooling systems still use ammonia as a heat transfer medium.
and yes it is hazardous...