Abstract: At 3:00 p.m. on November 8, 1995, employees of Russell Mechanical Inc., a mechanical construction company that had been contracted to upgrade the HVAC system of a cheese manufacturing plant, had sleeved an attic area with sheet metal and had finished the big supply ducts. Employee #1, a pipefitter, began painting the steel frame around a big supply duct and had thrown a plywood cover over the 22 in. by 47 in., 3/8 in. thick opening to the big supply duct, as directed by his foreman. Employee #1 was standing on the plywood cover to paint. After about 15 minutes, the plywood bent on the east, west, and north sides and tipped into the opening, causing Employee #1 to fall through the opening 19 ft 11 in. to the tile floor of the cheese manufacturing room. He sustained a burst fracture to his L-1 vertebrae that required surgery to fuse it to L-2, along with spinal cord injuries, groin, rectal, and foot problems.