High levels of the toxic substance cyanide have been released into the water from Fortum's Waste Solutions facility in Kumla for several months, according to P4 Örebro.
Fortum is allowed to release a maximum of 50 million liters of water from its treatment plant to a nearby lake every year.
In the end of January, high levels of cyanide began leaking out. It took over two months for Fortum to find the source and during that time, levels were measured at almost three times the amount allowed by the company. The waste had been stored without weather protection for several years, according to P4 Örebro.
Fortum claims that they are following their environmental permit and have handled waste in the past without the cyanide leaking. Their assessment is that there is no risk of the pollution spreading or affecting nearby residents or groundwater.
The company has stopped accepting waste and is investigating the matter internally.