The Janakkala study site is on a residential area on the premises of a single household. The leaking was due to a hole in a private heating oil tank dug in the ground, approximately 1 m from the north corner of the house. The tank is left intact, and is suggested to remain so by the landowner.
The site was studied in 2013/14 in relation to experimental remediation project. At the time it was concluded that the in situ bioremediation procedures had had minor effect on the contamination levels as high oil concentrations were found both before and after the treatment and the poor success was suggested to be connected to the low permeability of the soil.