TAMPA — Five men working on a large pipe at a wastewater treatment plant at the Port of Tampa were injured Thursday evening when exposed to toxic sewer gas, authorities said.
One suffered critical injuries, Tampa Fire Rescue said.
Four were hospitalized with what rescuers described as non-life-threatening injuries. A sixth worker there was not injured.
The contractors from Lanzo Lining Services were working on a section of 96-inch pipe at the city of Tampa's Howard F. Curren Advanced Wastewater Treatment Plant to install new lining.
"The incident occurred while the contractor was cleaning the pipe in preparation to install the liner," Anthony Kasper, director of the city wastewater department, said in an email.
The workers were either inside the 8-foot-diameter pipe or in a trench around it when the exposure occurred, said Emilio Salabarria, a division chief with Fire Rescue. Some collapsed inside and had to be helped out of the pipe, he said.
A call for medical assistance at the facility came in at 6:49 p.m. The victims' names had not been released Thursday night.
The plant handles all the wastewater treatment in the city. Its effluent either is discharged into Hillsborough Bay or used as reclaimed water. The contractor, which has offices in Deerfield Beach and Detroit, had been hired on a project to rehab the 96-inch pipe.
Although it hadn't been conclusively determined Thursday night just what fumes the workers were exposed to, Fire Rescue said in a media release it was likely hydrogen sulfide gas.
According to the Occupational Safety and Health Administration, hydrogen sulfide — sometimes called sewer gas — is a colorless, flammable and extremely hazardous substance common in wastewater treatment that can smell of rotten eggs.
Low concentrations irritate the eyes, nose, throat and respiratory system, OSHA says. High concentrations can cause shock, convulsions and stop breathing.
In 2005, three members of a cruise ship crew were killed after being exposed to hydrogen sulfide as they repaired a waste pipe aboard the ship in Los Angeles.