Abstract: In a building where telemarketing, accounting, and other work involving video display terminals was performed, an employee fainted, then another, and later a third on a different floor. Workers in the building became hysterical and alleged the presence of carbon monoxide (CO). The Pleasanton Fire Department responded with 2 fire battalions, 6 ambulances, and 17 ambulance personnel. A total of 26 employees alleged CO poisoning and were sent to 4 different hospitals. All were released within 4 hours. Air monitoring with direct readout instruments showed no CO, hydrocarbons, or hydrogen sulfide. Levels of oxygen and carbon dioxide were normal. The next day, the workers still alleged the presence of toxic chemicals in the building. Apparently, there were labor/management problems, widespread boredom with the work, and a lack of trust in management. No employees worked with any chemicals not normally found in offices, such as carbonless paper.