The rock room was used for the storage of diesel, mainly intended for civilian traffic in the event of a crisis or war, and was put into use as part of the total defense in 1976. In the 1990s it was decommissioned, like many other warehouses in the country.
Sweden’s Geological Survey (SGU), which discovered during an environmental inspection that the diesel was still in the rock room, has now started a cleanup because otherwise there was a risk that the oil would leak into Lake Mälaren, which is a source of groundwater.
— We have to find personnel who have experience in similar clean-ups. Among other things, we use a type of boat that is remotely controlled and travels on the surface to collect the oil, says Jakob Levén, at the Department of Land and Groundwater at SGU, to SVT.