The Vermont Supreme Court has ruled that the offsite migration of contaminants is insufficient, in itself, to establish a public nuisance. Vermont v. Howe Cleaners, Inc., No. 09-110 (Vt. 8/6/10). Affirming a lower court’s decision, the high court agreed that the state failed to demonstrate that perchloroethylene released on the subject property for some two decades and detected in a large groundwater plume had reached the level of a public nuisance.  

The state sued several parties, including the current owner of the property, which had formerly operated as a dry-cleaning establishment, seeking to recover costs it incurred cleaning up the perchloroethylecontamination. Under a state statute that provides a defense to a “diligent owner,” i.e., one who can establish that after making diligent and appropriate investigation he had no knowledge or reason to know of a release on the property, the lower court also ruled that the landowner was not liable because he had relied on a recent environmental assessment of the property.  

While the state supreme court affirmed this aspect of the ruling as well, it held that reliance on a valid environmental assessment may not always satisfy the diligent-owner defense—it depends on the facts of the case. Here, the supreme court found that the assessment was professionally and adequately