Abstract: At 9:00 a.m. on September 21, 1989, Employees #1 through #7 entered a work area at the Hyatt Hotel's Alpine Jack Restaurant to remove asbestos. An electric power washer was not working so a gasoline-powered machine was brought in as a replacement. The contained work area had 4,000 cfm negative air ventilation, which was not capable of removing carbon monoxide from the machine's exhaust fast enough to prevent carbon monoxide from building up to dangerous levels (estimated in excess of 200 ppm). By 11:00 a.m. the employees began to feel sick and by 12:30 p.m. they left the area, suffering from various symptoms. All seven employees were hospitalized and one required the use of a hyperbaric chamber.