UMichel Hart, ohlala eSan Diego, ubekwe icala lokwephula imithetho kahulumeni wase-US ehlose ukunqanda ukusetshenziswa kwamagesi abamba ukushisa. Akekho emthethweni ukungenisa ama-hydrofluorocarbons (ama-HFC) ngaphandle kwemvume ekhethekile ekhishwe yi-Environmental Protection Agency (EPA). UHart usolwa ngokuthenga izinto ezibandayo eMexico futhi azithengise e-US ngokuzifihla ngaphansi kwe-tarpaulin namathuluzi.