Five workers have been killed in an accident at a sewage treatment plant near the southern Italian city of Palermo, on the island of Sicily.
Another worker was found unconscious and taken to hospital.
The deaths are the latest in a series of workplace fatalities across Italy which have been causing anger among workers and trade unions.
The workers were found unconscious and not wearing masks, raising concerns about safety protocols at the facility at Casteldaccia.
They are reported to have succumbed to toxic gas poisoning, with one member of the team narrowly escaping the deadly fumes to raise the alarm.
“I heard them screaming but couldn’t do anything to save them.” Giovanni D’Aleo told the Italian daily La Repubblica. “I’m alive by some miracle.”
The men had been working in a 5 sq m underground tank accessible by a hatch at street level.
At the time of the accident, there had been a concentration of toxic gas 10 times higher than the danger limit.
When firefighters arrived at the plant of Casteldaccia, to the south-east of Palermo, seven workers were inside the facility. They retrieved the bodies of the five dead workers and rescued another in serious condition. The other man was found unharmed.
There has been no official statement from AMAP, the regional group responsible for wastewater treatment in the area.
The accident took place just a few weeks after an explosion at a hydroelectric plant near the northern Italian city of Bologna, resulting in the death of seven workers during maintenance operations.
“Full light must be shed on this tragedy,” Prime Minister Giorgia Meloni said on X.
“I hope that full clarity will be shed on the dynamics of the incident,” said Italian President Sergio Mattarella, during an official visit to the US.
“This unacceptable workplace tragedy, must forcefully reiterate the need for a shared commitment of all social forces, entrepreneurs and institutions.”