UNITED STATES
DEPARTMENT OF LABOR

Abstract: Employee #1 was using a rented Ingersoll-Rand air compressor to power a jackhammer to break up a bench in an approximately 2 ft wide by 5 ft deep manhole that belled out about 4 ft at the bottom. Employee #1 started the compressor, removed the manhole cover, lowered the jackhammer into the manhole, and then climbed in himself. With his feet on the bottom, the opening was level with the middle of his throat. After hammering for approximately 5 minutes, he squatted straight down into the manhole to put the broken concrete and bricks into a 5-gallon bucket. He stood back up and hammered for another 5 minutes, when he noticed that his face and hands were going numb. He managed to get out of the manhole and over to the operations building, where a coworker called 911. Employee #1 was eventually flown to the Maryland Shock Trauma unit and a hyperbaric chamber was used to remove the carbon monoxide from his system. According to Employee #1, his blood concentration of carbon monoxide was 18. The compressor had an exhaust leak at the muffler and heavy carbon buildup inside it. Its air intake was drawing in the carbon monoxide; the air that the jackhammer was using was enriched with the carbon monoxide and the exhaust from the jackhammer filled the manhole with carbon monoxide. Employee #1 had been exposed when he squatted straight down into the manhole. The employer did not have a confined space program.