Abstract: At 12:00 noon on August 27, 2021, an employee entered a tanker trailer to power wash the interior of the tanker. The tanker had contained animal parts, and was sitting outside in the high summer temperatures. The employee was found unconscious inside the tanker and emergency services were notified. Upon arrival, the fire department detected hydrogen sulfide at twice the level considered to be immediately dangerous to life and health at the open manway on the top of the tanker. No air monitoring had been done prior to entry into the tanker. No attendant was in place and there was no retrieval system set up to enable non-entry recue of the employee from outside the tanker. The employee died due to asphyxiation.