Abstract: On June 29, 2005, Employees #1, #2, and a coworker were assigned to replace a pump switch on a residential septic tank system. The 500-gallon lift station tank was pumped out. The coworker attempted to enter the lift station tank but it was too big to fit down the riser shaft, so Employee #1 entered the tank using a 10-ft metal folding ladder. Employee #1 was immediately overcome by methane gas and low oxygen levels and collapsed inside the tank. Employee #2 then entered the tank attempting to rescue Employee #1 and also collapsed. The coworker yelled to the homeowner to call for an emergency service. A first responder with county fire and rescue arrived and successfully pulled Employee #2 from the shaft, without entering the tank. They grabbed Employee #2's arm using a rope, which was looped at the end of a yard implement handle. Employee #2 was transported to the hospital where he died 5 days later. Employee #1 was pronounced dead at the scene.