[Frank said] Unfortunately, young teens and desperate drug users unscrew the caps off the freon service valves and use small tubing hoses to inhale the deadly freon to get a high. The freon robs the body of oxygen and give a short term high effect. Repeated used is required to maintain the high and it has been found that some vandals have spent many hours sitting next to a HVAC-R unit inhaling the freon until it runs out.  They wait for the facility to call in a repair company and refill the unit again, and the cycle starts all over again. 

The best way to avoid this problem to secure the equipment by locking your roof access ladder, installing chain link fencing around the unit and a video surveillance system or fake surveillance camera.  Harbor Freight sells a look alike, fake surveillance camera for about $15.00 money well spent as a cheap and easy deterrent.

 In closing, breathing freon is extremely dangerous to the body and will cause death or brain damage. It is a chemical that has serious consequences if inhaled.  Do not ever experiment with or breath freon of any form.