A federal judge has stopped three families who own homes near Love Canal in Niagara Falls from taking soil samples from the site unless the samples are shared with defendants in the case.

U.S. District Judge John T. Curtin, in a recent decision, said equal access to soil sampling is essential to preventing the destruction or alteration of potentially important evidence in the case.

The families filed suit against the City of Niagara Falls and several other defendants earlier this year, claiming the excavation of an underground sewer pipe led to the release of hazardous chemicals at Love Canal.