Attorneys general from 15 states along with conservation and property rights groups are backing Montana property owners in a U.S. Supreme Court case where the landowners are seeking compensation after a company dumped toxic waste into the community.

The states and several groups filed amicus briefs to the U.S. Supreme Court, which will decide the case Atlantic Richfield Company v. Christian by July. 

The U.S. Supreme Court will decide if the federal law establishing Superfund sites preempts the Montana Supreme Court from requiring the company to compensate the landowners.

The company’s smelter site near Opportunity, Montana, discharged toxic waste into the area for nearly a century and was later designated a Superfund site, which Atlantic Richfield Company and the EPA are required to maintain. Landowners affected by the pollution from the smelter site believe they should be compensated for their polluted property, but the company says federal law preempts the state court from requiring the company to do so.

“States have a strong interest in ensuring that their citizens (and the State itself) are compensated for injuries caused by releases of hazardous materials and in preserving their authority to address, respond to, and remediate harm from environmental contamination,” Virginia Attorney General Mark Herring and others said in the brief. 

Herring was joined by attorneys general in California, Connecticut, Delaware, Hawaii, Maine, Maryland, Mississippi, New Jersey, New York, Oregon, Rhode Island, Vermont, Washington and Wisconsin.

The Property and Environment Research Center, a free-market environmental group, and the Pacific Legal Foundation, a civil liberties law firm, argued in an amicus brief filed  recently that the company’s argument undermines property rights.

“Secure property rights discourage environmental damage by forcing would-be polluters to internalize the harms imposed on neighboring property owners,” lawyers for the organizations write. “And where this incentive isn’t heeded, property rights enable anyone whose property is damaged by another to demand that property be restored. Where property rights are insecure, these incentives are weakened, leading to worse environmental outcomes.”

Other groups that filed amicus briefs were Public Citizen, and the Clark Fork Coalition and Montana Environmental Information Center.