Abstract: At 1:00 p.m. on October 12, 2021, twos employee was were operating cashier registers and assisting customers at a grocery store. Employee #1 started having a headache, feeling dizzy, and having difficulties breathing. Employee #2 told Employee #1 to sit down when she noticed her not feeling well. When Employee #1 sat down, she began to feel worse and started losing consciousness. When Employee #2 noticed that Employee #1 was unable to respond to her questions, Employee # and her supervisor called 9-1-1. When the fire department arrived at the scene and entered the building, the carbon monoxide sensors on the fire fighters' bags started alarming. The building was evacuated and Kansas Gas and a Hazmat team were contacted to conduct air monitoring and identify the source of the carbon monoxide leak. A food warmer was identified as the source. Employee #1 and #2 were hospitalized and treated for carbon monoxide poisoning.