Belfry Volunteer Firefighter Darrell Helton died Wednesday evening while on a mutual-aid call in McCarr, Kentucky.
Helton, 49, experienced a heart attack after transporting water to a structure fire alongside a neighboring department, WCHS reports.
According to the incident report, Helton reported feeling a fluttering in his chest before collapsing after delivering a water load.
Despite immediate CPR and transportation to a local hospital, efforts to resuscitate him were unsuccessful.