Three men suffocated Saturday morning as they were cleaning a water tank at a spinning mill in Toyo, Ehime Prefecture, police said.
Saburo Saiki, 63, Shigeki Matsuyama, 61, and Yasuto Kumabe, 68, were found collapsed at around 6:40 a.m., and were pronounced dead shortly afterward, police said. They apparently died from a lack of oxygen in the tank, said police, adding that it was also possible that the victims inhaled poisonous gas generated within the tank.
The three were removing waste water and sludge from the tank, which is located in a mill in an industrial district near JR Nyugawa Station, they said.