Do the right thing and take that shit to be properly disposed of--if you have access to it, report where that access is coming from.
CFCs are INCREDIBLY DAMAGING to the ozone.
They are very light molecules and so they drift upwards very easily. They can make residence in the outer atmosphere for hundreds of years. They act as a CATALYST to deplete the ozone layer--not a reactant. That is to say, they are not "used up" by the depleting reaction. Each time they complete a reaction, they move on to another ozone molecule and destroy it as well--this reaction happens millions of times a minute with 1 molecule of CFC.
Do not use this stuff, do not take it out of the tank.