Abstract: At approximately 11:00 a.m. on September 5, 2006, Employee #1, a sewer worker, entered a sewer to manually clean and vacuum. Two other workers stayed at street level. No atmospheric readings were taken prior to the worker's entry into this combination sanitary and industrial 60-inch sewer that was approximately 35 feet below street level. Employee #1 entered the sewer without any respiratory protection and was not tied off for retrieval or emergency rescue. He worked in the sewer for approximately one hour and during this time the two other workers, both of whom were at street level, observed that the odor coming from the sewer was becoming stronger. Employee #1 came back to street level for approximately 10 minutes, complaining of difficulty breathing. Against the warnings of the other two workers, he went back into the sewer, again without any atmospheric readings being taken and no personal protective or rescue equipment. A few moments later, the attendant was not able to communicate with Employee #1 and called emergency services. Rescue crews arrived, retrieved him from the sewer, and transported him to the hospital where he died less than 24 hours later. Readings obtained by the rescue crew, prior to their entry, indicated high levels of hydrogen sulfide. Readings obtained from the Northeast Ohio Sewer department, taken shortly after the accident, showed high levels of ammonia.