Abstract: On February 13, 1989, Employees #1 and #2 and coworkers were attempting to bring the Southwest Regional Water Treatment Plant back on line to purify and chlorinate drinking water for sandy water users. A chlorine leak developed and Employees #1 and #2 used several bottles of air on SCBA trying to pinpoint the leak without success. While Employee #1 was initially investigating, one of the two exhaust vent systems did not come on because of a tripped circuit breaker, and he was exposed to chlorine fumes. Employee #2 was exposed when he ran into the chlorinator room without SCBA and after the vent system had been intentionally shut down. Both employees were hospitalized. These exposures resulted from the employees not following written procedures.