Three men died after they were found suffering cardiac arrest in a hot spring village in northeastern Japan, police said.

Firefighters suspect the men were exposed to hydrogen sulfide.

The three were working to adjust the temperature and amount of hot water near a source of the Nyuto Hot Spring in Senboku, Akita Prefecture.

The victims were identified as Sakae Sakamoto, 78, Tsugiyoshi Hanegawa, 67, both working for a local company, and Masafumi Shibata, 42, a Senboku municipal official.

Sakamoto and Hanegawa fainted first when they walked 200 meters from the hot spring source to pick up their carry bags, and Shibata collapsed while trying to help them.

Around 300,000 people visit the secluded Nyuto Hot Spring area every year, according to the local government.