Abstract: Employees #1 and #2, along with coworkers, were constructing a pump station for a sanitary sewer main project. The pump station excavation was about 18 ft by 18 ft and 27 ft deep, and 13 piles had to be driven into it so that the precast station placed inside would have ample support. On August 26, 1992, the first pile was water jetted and driven in the excavation. A foreman entered the excavation; thereafter, he was ill and said he thought there was gas in the excavation. The project engineer and another foreman left the site to see if they could obtain blowers. But during their absence, a "quick" condition began developing in the excavation. They returned to the site and the decision was made to flood the excavation to keep it intact. When Employee #1 entered the excavation to collect tools and equipment, he was overcome. Employee #2 then entered the area to rescue Employee #1, but he, too, was overcome. Using a crane, Employee #1 was retrieved by the foreman who first commented on the gas condition, and was hospitalized at a local facility for several days. Employee #2 was eventually retrieved through the combined efforts of the local police, fire, and other rescue personnel, although one police officer died during this rescue operation. Employee #2 was taken to the University of Maryland for treatment in a decompression chamber. While his condition was originally critical, he survived and was eventually released home. There had been no emergency rescue equipment at the site, and monitoring of the excavation had not been performed, even though in May 1992 the company had been advised by the county health department to monitor excavations on the project. The hazardous atmosphere inside the pump station excavation included, but was not limited to, hydrogen sulfide.