WASHINGTON — The Supreme Court appeared skeptical Monday of allowing Colorado officials to sue fossil fuel producers in state court over the impacts of climate change, opening the 2026-27 term by taking on a case with far-reaching implications for the US energy industry.

“Presumably if you prevail, the next day a municipality in every single state will file a lawsuit, copy your pleadings and then there’ll be at least 50 …. causes of action filed. How do you think that will work out?” Chief Justice John Roberts asked an attorney for the Boulder County Board of Commissioners.

“There’s always going to be greenhouse gas emissions affecting every state.”

Monday’s case involving Suncor Energy was heard by eight justices rather than the usual nine, as conservative Justice Samuel Alito recused himself following scrutiny over his holdings in oil and gas companies.

The case originated in 2018, when Boulder sued Exxon Mobil and Canada-based Suncor demanding they “share a portion of the financial burden their communities must bear in coping with an altered climate brought about in part by petitioners’ tortious conduct.”

Both companies argued that federal law prevented the suit from proceeding, but the Colorado Supreme Court ruled last year that the case could move ahead.

The justices are weighing both whether the Colorado Supreme Court’s ruling is reviewable and — more importantly — whether the Constitution and federal Clean Air Act prevents Boulder from pursuing its claims in state court.

Justice Brett Kavanaugh cited four precedents that he suggested vindicated Suncorp’s position and “make crystal-clear that interstate air and water pollution are matters for federal law unless Congress specifically preserves state law.”

Kavanaugh implored Suncorp’s attorney to focus on the Clean Air Act rather than suggesting the Boulder lawsuit undermined the federal government’s control over foreign policy as well as interstate commerce.

The energy companies have asked the Supreme Court for a broader ruling, since legal claims against them might survive under the Clean Air Act, as one of the liberal justices pointed out.

“We’ve been talking a lot about these constitutional principles,” Elena Kagan told an attorney for Boulder at one point. “Your friends have indeed relegated the Clean Air Act to a couple of pages.”

“But I’m wondering if that isn’t a more natural and simpler route towards their view of what should happen here,” she added. “The Clean Air Act sets up an extremely complicated scheme of how regulations of emissions should operate.”

Both Roberts and fellow conservative Amy Coney Barrett asked why Boulder was targeting energy producers for damages rather than fossil fuel emitters like industrial manufacturers, with Roberts pointing out: “The fuel production itself doesn’t have the universal harm that we’re talking about.”

Kevin Russell, arguing for the Boulder commissioners, argued that there was no basis in law to pre-empt the state court lawsuit.

“Since the founding, states have had the power to provide tort remedies for injuries occurring within their borders, even when the conduct causing those injuries occurred elsewhere,” he argued.

“They [Suncor] invite this court, defined in the structure of the Constitution, a judicial power to declare some subject matters inherently federal and therefore preempted not by congressional enactments, but by congressional silence.”

If the high court deadlocks 4-4, the lower court ruling will stand, allowing the suit to proceed.

A decision in Suncor Energy Inc. v. Commissioners of Boulder County is expected by the end of June.