Officials in south-west Finland have pinpointed the source of radiation detected from a load of scrap metal in the municipality of Eurajoki, site of the Olkiluoto nuclear power plant. They determined that the radiation source is a device probably used to measure soil moisture and density. "Based on the pictures I have received, it is a relatively rare, old device," says Santtu Hellsten, a section head at the Finnish Radiation and Nuclear Safety Authority (STUK) told Yle on Tuesday morning. Later in the day STUK announced that the instrument was identified as one used by the Finnish Environment Institute (SYKE) in the 1970s. Hellsten tells Yle that the recycling firm acted properly by contacting STUK after detecting radiation in a load of waste. STUK asked the local rescue squad to measure the radiation level at the site and then declared that it did not pose any danger to people or the environment. On Monday STUK sent two experts to investigate in Eurajoki, some 40 km south of Pori. They continued their work on Tuesday. "This is quite rare. These [cases] come up every couple of years, maybe even less frequently," said Hellsten. He says this was clearly a case of careless disposal of a radiation source. "This kind of device requires a safety permit as it contains a radiation source. It emits some radiation into its immediate vicinity, but is no danger to anyone who is further away," Hellsten explains. At the moment there are about 100 soil moisture meters or hygrometers listed in STUK's safety registry. However the permit for the device in question expired years ago. "It is a relief that the origin of the device will not remain a mystery," Hellsten said after the item's provenance became clear. "The user of the device is responsible for its disposal, so now we know who will pay for the costs." The meter apparently ended up in a waste container during renovation of the SYKE headquarters in Helsinki, and was transferred for processing at the Eurajoen Romu recycling facility - which is coincidentally about 20 km from the Olkiluoto nuclear plant, where all radioactive waste is now stored in a temporary facility. In cases where the origin of such items cannot be determined, the state is responsible for its disposal. Alternately the item may be returned to the importer or manufacturer. The case may still spark a police investigation. Last month STUK revealed that radioactive material had been sent several times to a smelting plant in Tornio, northern Finland.