Five men in their 40s and 50s who worked for a chemical company handling dyes and pigments have developed bladder cancer, the health ministry said Friday.
The ailment is uncommon and attention has focused on the possible absorption of carcinogens at the factory.
The health ministry asked two chemical industry bodies — the Japanese Chemistry Industry Association and the Japan Dyestuff and Industrial Chemicals Association — to safeguard workers from exposure to certain chemicals by making sure they wear gas masks and get proper ventilation.