Abstract: On October 10, 2002, Employees #1 and #2 and two coworkers, of the Electrical Technologies Corporation, were installing PVC pipes in a trench to run cable through it. This duct would then connect to the 10 ft deep by 3 ft 3 in. wide manhole located nearby. Water from the manhole was seeping into the trench through the window outlets that connected the two, and the crew decided to use a pump to purge the water from the manhole. The manhole opening was located 5 ft away, but the trench was dug up to the point of the manhole walls. Employee #2 entered the manhole to unclog the pump hose when he became overwhelmed by the atmospheric conditions and fell, face down, in the water. Employee #1, the foreman, went in to rescue him and also loss consciousness. When one of the coworkers tried to help them, he became dizzy and immediately exited the manhole. Employees #1 and #2 died of hydrogen sulfide exposure and were pronounced dead at the scene. The fire department took readings of the atmosphere and purged the manhole prior to sending in its rescue crew.