Abstract: On April 26, 2001, Employee #1 died when he entered into a confined space vault area. He was working at a construction site when he became ill and collapsed. His employer was working on a flight line at Air Force Plant Number 42 on a project for Northrup. The general contractor was Amelco. Employee #1 was working for Gall Brothers Engineering. The project was removal and replacing of underground fire protection pipelines. The lines were water lines only and no gas or electrical lines were in the vicinity. The pipelines were under the tarmac, and had been dug up. The company was preparing to remove asbestos-bearing material before removing the pipes from the pipeline and from the concrete vaults located every quarter mile along the pipeline. The pipeline was made of 8-inch-diameter metal pipe. The concrete vaults were underground and measured 5.5 feet by 5.5 feet, and 6 ft deep. Access was through a round, 2-foot opening in the top of the vault. Two employees were present. Their job was to remove metal pipe from outside of the vault, and later, when ventilation was provided, from the inside of the vault. The general contractor stated that his foreman explicitly told all employees, including Employee #1, to stay out of the vaults until their confined space program could be activated. The employer stated that he also specifically told both men to not enter the vault. However, Employee #1 entered the vault to cut a pipe with a gasoline-powered cut-off saw. The saw was a Speedicut (Model Number SC7314). One witness stated that he told Employee # 1 to not go into the vault. The witness stated that Employee # 1 went in anyway. He was in the vault only a few minutes. Employee # 1 exited the vault, then after a short rest, Employee #1 returned to the vault, made another cut, then came out again. The witness stated that Employee #1 had been in the vault for less than 15 minutes. The witness stated that Employee #1 at this time (after leaving the vault the second time) did not appear to be feeling well. He was sweating profusely and his color was wrong. Both employees stopped work and took a break. Both men returned to work, using a jack hammer down the pipeline from the vault. After about 30 minutes Employee #1 became ill, with vomiting and chest pain. The owner arrived on the scene. He observed the condition of Employee #1 and immediately called an ambulance who transported Employee #1 to the hospital. He died en route. According to LA County Coroner, Employee #1 had suffered a heart attack. The autopsy showed that he had serious heart disease, and had suffered a heart attack previously. He had a blood carboxyhemoglobin of ten. He was a heavy smoker, so this amount was predictable and not necessarily indicative of an exposure. Air monitoring was done by Northrup Grumman about 3 hours after the incident. The lid had been left open. At that time, the Carbon Monoxide and Oxygen levels were normal, and there were no other abnormalities found. The vault was a confined space, which the employee entered without taking the appropriate precautions. He operated a gasoline-powered saw, which generated Carbon Monoxide at unknown levels. Employee #1 had a preexisting condition, which may have been aggravated by the Carbon Monoxide exposure. Employee #1 had not been trained in confined space hazards.