Abstract: Sewer pipe liners were being installed into a 72 in. sewer pipe. Employees #1 and #2 entered the sewer pipe to check the fit of the new liner. Neither employee wore an escape-type respirator, had a safety harness or lifeline attached to them, nor had specified training for this type of work. The employer had removed the ventilation fans prior to the employees' entrance into the sewer line and had not tested the area. A working test unit was not available for usage, nor did either of the employees wear a warning device. Employees #1 and #2 were overcome by noxious substances and Employee #1 was hospitalized. Employees #3 and #4 underwent treatment for burning eyes. No employee wore a full face respirator or effective eye protection.