Abstract: At 1:00 p.m. on July 18, 2023, an established HVAC technician employee with a pre-existing heart condition working for a mechanical contractor collapsed in the restroom of a retail store, his second job that day. Earlier the employee drove over 2 hours to access (interiorly) a flat roof at about 10 am for about 20-30 minutes, where he performed light maintenance. He then drove about 45 minutes to the second job, attended to the inside thermostat, went back and forth to the work van a couple of times (telematics shows it was running), and began to appear uncomfortable before going to the restroom and phoning for assistance stating he had lost feeling below his waist. After EMS arrived onsite he lost consciousness. EMS administered CPR before transporting the employee to the local hospital. The employee later died from a heart attack. All the employee's time inside the customers' stores and in the van was air-conditioned. The incident was determined not to be a heat- or work-related injury.