The following is an abridgement of an article originally published on the OSHA website.
A 34-year-old worker from a plumbing contractor company died after falling 20 feet into a manhole and inhaling hydrogen sulphide gas whilst working at a school in Georgia, USA. The company was replacing a sewer line when a blockage in a pipe was found. In order to clear the blockage near the end of a 60-foot-long-trench (~ 18 metres), one worker entered a manhole. Shortly after, the worker fell 20 feet (~ 6 metres), experienced injuries from the fall and exposure to a high atmospheric concentration of hydrogen sulphide gas.
OSHA investigated the incident and found that the company violated several standards for trenching and excavation work.
The Fire Department used a gas monitor to test the air inside the manhole and found the presence of hydrogen sulphide at 1,910 parts per million. The OSHA permissible exposure limit for hydrogen sulphide is 20 ppm. An environmental concentration of 100 ppm is considered immediately dangerous to life or health.
OSHA cited the employer for wilfully failing to develop and implement a permit-required confined space entry program, including testing and ventilating the space, before allowing employees to enter a manhole. The agency also cited 6 serious violations for not providing ladders or other safe means of egress from the 6-foot-deep trench and protections or controls for water accumulation inside the trench.
In addition, the employer failed to have a competent person inspect the trench prior to workers entering and for not ensuring excavated soil and uninstalled piping were stored at least two feet from the trench edge, preventing them from rolling back inside the trench and striking workers.
As a result, OSHA proposed $184,387 in penalties and cited the company for wilful and serious violations.
OSHA said the company’s failure to adhere to industry guidelines resulted in a preventable loss of life. The agency urged employers to implement safety controls and train employees to recognise and avoid hazards.
Among the industry's most dangerous hazards, unsafe trenching and excavations led to 40 construction workers suffering fatal injuries in 2022.