Facts
[A. AG] , the legal successor of [C. AG] , was qualified as the responsible party or causal agent, as [C. AG] manufactured aluminium tubes and ignition coil casings on the property from 1949 to 1962 and used tetrachloroethylene for cleaning, which led to groundwater contamination. [B. AG] , which acquired the property in 2012, was classified as the current responsible party or causal agent. The Building and Justice Department of the Canton of Solothurn distributed the costs for the investigation and remediation in the ratio of 80% to [A. AG] and 20% to [B. AG] . This cost distribution was confirmed by the Administrative Court of the Canton of Solothurn and the DFC.Considerations
The DFC stated that the obligation to bear the costs under Art. 32d EPA exists regardless of whether the causative act was in line with the state of the art and approved by the authorities at the time. The fact that the remediation liability did not yet exist at the time of the merger in 1968 between [D. AG] and [A. AG] does not preclude [A. AG] 's…