Vein: A blood vessel that carries blood that is low in oxygen content from the body back t... See the entire definition of Vein Viral: Of or pertaining to a virus.
This means that breathing low concentrations of freon from a leaking refrigerator or air conditioner over a long period of time is unlikely to have a cumulative effect, and thus few, if any, long term health effects.
Replace because of Freon Leak. I had a freon leak 3 years ago when my A/C was 9 years old. (It's a 3.5 ton Trane system, with the main unit outside and the air handler in the attic). They added freon then and the system had been OK until 3 weeks ago, when it froze up.