Four people have so far complained of illness in a town near Hokkaido's Niseko mountain resort after steam erupted during drilling for a geothermal energy development project, Mitsui Oil Exploration Co. said Saturday.
A high level of arsenic has been detected from water collected near the site in Rankoshi. Mitsui Oil, which is in charge of the project, said it is looking into what caused the illness, although it refrained from giving any details of the symptoms for privacy reasons.
Mitsui Oil began drilling on June 25 to survey the potential resource, and the steam erupted four days later.
The first two reports of illness came earlier this week -- a woman who delivered lunch at the site and was temporarily admitted to a hospital for hydrogen sulfide poisoning, and a resident of Rankoshi -- but the company said Saturday that two more people have said they are also not feeling well.
No health problems have been reported from the 18 workers who were at the site at the time of the incident.
According to the company and the town, the arsenic level detected from the nearby water was 1,590 times higher than the standard for drinking water and 318 times higher than that for water for agricultural use.
