High Levels of Arsenic Detected at Steam Spews in Hokkaido

The Yomiuri Shimbun

13:44 JST, July 8, 2023

RANKOSHI, Hokkaido — High levels of toxic arsenic have been found in water at a geothermal power generation research site in Rankoshi, Hokkaido, after a large quantity of steam has been erupting for over a week. Three people have complained of health problems, such as hydrogen sulfide poisoning.

On Friday, the municipal government lodged a protest against Mitsui Oil Exploration Co., which conducts research at the site in the Niseko mountain range.

According to the company, steam began spewing out from a well that had been drilled for research on June 29. The steam has caused the surrounding forest to turn white and water in a nearby stream to become cloudy. The company announced Thursday that 15.9 milligrams of arsenic per liter of water was detected in a sample from the site. The figure is 1,590 times higher than the standard for drinking water.

Arsenic was also found in nearby rivers, prompting temporary water restrictions on farmers for agriculture.

The company apologized for inconveniencing local residents and said it is considering measures to prevent the steam from pouring out.