Abstract: At approximately 5:00 p.m. on November 7, 2019, an employee was working at a full-service restaurant. He was working as the general manager, and he was overseeing the operation of the restaurant. At least two coworkers were present at the time of the incident. The first coworker was a cook. The employee was working with the cook to clean and organize the back hallway of the restaurant. The second worker present was the assistant general manager. The employee would be transferring control of the restaurant to the assistant general manager soon. Employee #1 left the cook to clean the area. The assistant general manager arrived to start working shortly after the employee left the area. The assistant general manager had a brief conversation with the cook. Shortly after that, the cook poured a gallon of Super 8, a sodium hypochlorite-based disinfectant, all over the floor of the back hallway. The cook then left the area. When he returned, he poured a gallon of Scale Kleen, an acid-based scale remover, all over the back hallway. The second liquid combined with the Super 8. The cook then began to scrub the floor with a long-handled brush. The combination of these cleaning chemicals resulted in the creation of a toxic atmosphere. The fumes were irritating to the respiratory tract, eyes, and skin of the people in the immediate and surrounding area. The cook notified the assistant general manager of the problem. The assistant general manager attempted to clear the mixture out of the back door of the restaurant. The cook had propped the door open. The employee took over the effort of squeegeeing the combination of cleaning chemicals out of the back door. He was soon overcome by the fumes. He sustained a seizure from which he did not recover. Following his noticeable debilitation, the coworkers contacted emergency services. They took over control of the scene when they arrived. The employee was taken to a hospital. The employee was declared dead at the hospital. Meanwhile, between the time emergency services had been contacted and their arrival, the cook continued to squeegee the combination of cleaning chemicals out the back door. He also went through the danger area to the kitchen to remove some food from the fryer. He was one of many of the restaurant workers who initially evacuated through the danger area. Several of these workers also returned to the danger prior to any evidence that the hazardous atmosphere had subsided. Only the employee, the cook, and the assistant general manager were involved directly in the response to the incident. The employee died as the result of this incident. His employer believed that a pre-existing medical condition contributed to his severe reaction. Numerous other workers sustained varying degrees of irritation to their respiratory tracts, eyes, and skin. Eight workers were admitted to the hospital for observation and testing and released shortly thereafter. According to reports by the Burlington MA police and fire departments, six other individuals were also admitted to the hospital for the same reason. The toxic atmosphere created by the combination of the Super 8 and the Scale Kleen was the cause of the harm.