Abstract: Employees #1 and #5 through #7 were near the chlorine unloading area at a bleach plant when the gasket of a recently-installed vaporizer failed, releasing between 500 and 700 gallons of liquid chlorine. When Employees #1 and #7 went to investigate the extent and location of the leak, they found an overwhelming concentration of the chemical. They were not using SCBAs, nor was Employee #6, who used the wrong escape route. Employee #5, the bleach plant operator, attempted to find and assist Employee #6. Employees #2 through #4 attempted to shut down the vaporizer system but they did not know the location of the one critical shut-off valve, and the key person was not immediately available to help. Employees #1 through #7 suffered chemical burns from inhaling the chlorine fumes; all were hospitalized except for Employee #2.