In accordance with the present invention compositions are disclosed. The compositions consist of (A) a refrigerant component consisting essentially of (1) at least one refrigerant having an OEL less than 400; and (2) a combination of refrigerants, each having an OEL greater than 400, consisting essentially of (i) HFC-32; and (ii) trans-HFO-1234ze; and optionally (B) a non-refrigerant component; wherein component (A)(2) of the refrigerant component is present in an amount sufficient to provide an overall OEL for the refrigerant component of at least 400. The refrigerant mixtures of the refrigerant component are useful as components in compositions also containing non-refrigerant components (e.g. lubricants), in processes to produce refrigeration, in methods for replacing refrigerant R-410A, and in air conditioning and heat pump apparatus.