UNITED STATES
DEPARTMENT OF LABOR

A three-man construction crew was overexposed to carbon monoxide generated from the exhaust of a 25 horsepower gasoline fueled engine being used to power a concrete cutting chainsaw. The employees were sent to a construction site to cut a 16-inch by 16-inch square hole in a concrete wall so that an exhaust fan could be installed. The wall to be cut was located on the third level of a concrete tower, the Mill Feed Loadout facility, still under construction. The 25-foot long by 16-foot wide by 24-foot high room had little or no ventilation. Employee #1 operated the saw for approximately 15 minutes initially. He got tired and traded jobs with Employee #3 who was vacuuming water. Employee #2 held the vacuum hoses during the entire duration of the job. Employee #1 began feeling bad and went to the second level for fresh air. Employee #3 operated the saw for approximately 15 more minutes and then decided to stop so that an anchor could be installed. Employee #3 walked over to the engine and cut it off. On the way back to the saw, Employee #3 passed out. Employee #2, who was still holding the vacuum hose, tried to get to Employee #3 but was also overcome and passed out. Employee #1 had just come back up the ladder to the third level to check on the other two employees when the engine was cut off. Employee #1 kept asking if they were okay. Employee #1 saw both pass out and decided to go to the ground level for help. All three employees were hospitalized for carbon monoxide exposure.