A high school hosted several events in their gymnasium over a weekend. The event on Saturday proceeded in exemplary fashion. During the next day’s event, attendees in one section of the stands experienced intense eye, skin, and respiratory irritation, headache, and nausea. EMSL asked the school’s consultant what had occurred in the gym between the events. It turns out that the custodial staff had cleaned after the first event. The MSDS for the disinfectant used indicated that the material contained compounds that could cause the irritation noted. The consultant performed wipe sampling in affected and unaffected areas of the stands. EMSL determined that high concentrations of the disinfectant were present in the affected area, and not in unaffected areas.