Abstract: At 2:30 p.m. on April 30, 2019, an employee from a temporary employment agency began his first day as a line worker for a firm that was engaged in millwork, including flooring. He was a machine operator, and he worked on a press line. On the line, he worked filling cracks and knot holes in floorboards before they went through a planer. He was at a worksite, that of a firm that provided general storage and warehousing. His employer, the millwork firm, was sharing the building occupied by the storage and warehouse firm. The warehouse firm had a Caterpillar model CG55KSTR powered industrial vehicle (PIV) that it used for material handling operations. Warehouse employees operated it for some 2.5 hours daily. It ran on liquid petroleum (LP). It was provided by an outside firm that also performed maintenance. On April 30, 2019, the Caterpillar had fuel flow issues that caused it to produce concentration levels of carbon monoxide (CO) in excess of 50 ppm. After two or three hours, the millwork firm employee developed a mild headache. Throughout the day, his headache grew so strong that when he got home after work, he had his wife take him to the hospital. The hospital analyzed his blood and transported him to a bigger hospital, for treatment of elevated carboxyhemoglobin. He was hospitalized. From the analysis of the blood drawn at the first hospital, it was calculated that the employee's 8-hour carbon monoxide time weighted average exposure was 223.8 ppm. He had had been exposed to 440 percent of the 8-hour time weighted average carbon monoxide exposure limit of 50 ppm. On May 2, 2019, the PIV had an emissions test. The carbon monoxide level in its exhaust was measured at 4.28 percent. Two other employees at the site were exposed to carbon monoxide, but they were not hospitalized. An OSHA inspector measured baseline CO level in the warehouse at 66 ppm. With the doors closed and the PIVs operating, a lift truck firm employee measured the CO level at 42,300 ppm.