Existing regulations affecting systems containing 50 pounds or more of class 1 or 2 refrigerants (I.E. R22, R12) was expanded to include any system containing 50 pounds or more of any non-exempt refrigerants. 40 CFR 82.154 list exempt refrigerants as Carbon dioxide in any application; Nitrogen in any application; Water in any application; Ammonia in commercial or industrial process refrigeration or in absorption units; Chlorine in industrial process refrigeration (processing of chlorine and chlorine compounds); Ethane (R-170) in some applications; Propane (R-290) in some applications; Isobutane (R-600a); R-441A in some applications.