Which gases are used in refrigerator?

The gases used for the refrigeration are mainly halogenated compounds

of methane gas.

They are less toxic and less flammable.

But they can cause a person to be dizzy if inhaled. 

But these gases can pose suffocation hazards as they can displace oxygen 

in confined spaces like inside the refrigerator. 

But these gases can cause global warming as these are greenhouse gases.