I have searched all over the internet trying find the actual R-134a laws. I read through through the EPA sections that refer to 1,1,1,2-Tetrafluoroethane.
Everything I find is about it's safe handling.
While reading through the EPA PDF I found that 1,1,1,2-Tetrafluoroethane is vented to the atmosphere in most of is uses.
I have a feeling that 100% of the R-134a that they sale at auto part store, Walmarts and gas stations is eventually vented into the atmosphere.
This is the description they give.
1,1,1,2-Tetrafluoroethane is a hydrofluorocarbon and haloalkane refrigerant with thermodynamic properties similar to R-12 but with insignificant ozone depletion potential and a significantly lower global warming potential.
Other uses include plastic foam blowing, as a cleaning solvent, a propellant for the delivery of pharmaceuticals (e.g. bronchodilators), wine cork removers, gas dusters, such as Dust-Off, and in air driers for removing the moisture from compressed air. 1,1,1,2-Tetrafluoroethane has also been used to cool computers in some overclocking attempts. It is the refrigerant used in plumbing pipe freeze kits. It is also commonly used as a propellant for airsoft airguns. The gas is often mixed with a silicone-based lubricant.
Until I see something that says it's okay to dump our R-134a I'm not going tell anybody to do it. But it seems like it's common practice to vent 1,1,1,2-Tetrafluoroethane into the air everyday.