Abstract: At approximately 04:00 p.m. on July 05, 2021, an employee working under a 638 contract was working as a camp crewmember on the Sylvan Fire. The employee was demobilized from the fire on July 05, 2021. As the employee was headed back to Fort Hall Agency, she began to feel unwell and was difficult to wake by other coworkers. The camp supervisor notified EMS, and the employee was transferred to Spanish Fork Hospital is Utah. The employee was diagnosed with dyspnea, vomiting and anemic but was released later that night. As directed by ER staff, the employee sought additional medical treatment the next day from the local hospital, Bingham Memorial Hospital in Idaho. The employee was then diagnosed with mountain sickness and hyperthyroidism. At approximately 07:00 p.m. on July 24, 2021, the employee died at home from what was initially determined to be work related injuries, but the Bannock County Coroner later determined the cause of death was from natural causes.