Abstract: A SUPERMARKET WAS TO BE TAKEN OVER BY NEW OWNERS ON AUGUST 12, 1985. ON AUG 11, 1985, THE STORE WAS CLOSED AT 6 PM. FOR AN INVENTORY AND SOME REMODELING. THE CASH REGISTERS WERE ALSO TO BE MOVED. A TRENCH, 22 INCHES WIDE AND 80 FEET LONG, HAD TO BE CUT IN THE CONCRETE FLOOR. THE NEW OWNER HIRED A MASONRY CONTRACTOR AND ELECTRICAL CONTRACTOR TO DO THE WORK. THEY ARRIVED AROUND 6:30 PM. THE MASONRY CONTRACTOR BROUGHT IN A GASOLINE-POWERED MASONRY SAW, 65 HORSEPOWER, CIMLINE BRAND. SAWING TOOK PLACE FOR TWO TO TWO AND A HALF HOURS. NO MECHANICAL VENTILATION OR EXHAUST PIPING WAS USED. AROUND 9:30 PM, THE ELECTRICIANS'S DAUGHTER, AN APPRENTICE ELECTRICIAN, PASSED OUT NEAR THE TRENCH. SHE HAD BEEN ASSEMBLING ELECTRICAL APPARATUS TO BE INSTALLED IN THE TRENCH. OTHER EMPLOYEES ALSO BECAME SICK AND WENT OUTSIDE. THE FIRE DEPARTMENT WAS CALLED TO VENTILATE THE STORE. WHEN THEY ARRIVED EIGHT EMPLOYEES WERE LYING ON THE PARKING LOT OUTSIDE THE STORE. VENTILATION WAS CONTINUED FOR ONE HALF HOUR. A CARBON MONOXIDE READING WAS TAKEN. THE LEVEL WAS STILL 200 PPM ABOUT TWENTY FEET FROM THE INCOMING FANS. AMBULANCES WERE CALLED AND A TOTAL OF 19 PEOPLE TAKEN TO THE HOSPITAL FOR CARBON MONOXIDE POISONING. THEY WERE VENTILATED, AND BLOOD TESTS TAKEN FOR SEVERAL HOURS. THE THE 19 EMPLOYEES WERE FROM A TOTAL OF 5 COMPANIES. ELECTRIC SAWS WERE AVAILABLE FOR USE IN THE STORE BUT WERE NOT USED.