The Yuma Fire Department responded to the La Mesa Care Center on South Arizona Avenue Thursday afternoon after a smoke alarm went off at the business. When fire department personnel arrived, they noticed what they described as a slight purple haze in the building, but there was not any smoke. The room and surrounding wing of the care center was being evacuated. The vapor haze was due to a room air conditioning unit that had failed and leaked its Freon refrigerant into the room. The unit was removed and the room was ventilated to disperse the refrigerant. Three patients at the facility were checked out and transported to Yuma Regional Medical Center for further evaluation as a precaution. Several facility workers were also checked out but not transported.