Abstract: At approximately 6:00 a.m. on April 23, 1999, Employee #1 entered a facility to begin work. She walked through the office to the kitchen area and passed out on the floor. Employee #1 was overcome by carbon dioxide which had been leaking in the shop overnight from the 14-ton carbon dioxide pressure vessel used for filling cylinders. Employee #2 and Employee #3 entered the facility approximately 40 minutes later in an attempt to rescue her and succumbed to the carbon dioxide as well. Employees #1, #2, and #3 were taken to the hospital. Employee #1 never regained consciousness and died on April 26, 1999. Employee #2 and Employee #3 were treated and released.