DENVER—A federal appeals court decision overturning a $926 million verdict against the operators of the Rocky Flats nuclear weapons plant is likely to affect climate change lawsuits that allege defendants created a “public nuisance,” legal experts say.

In the Sept. 3 decision in Merilyn Cook et al. vs. Rockwell International Corp. and Dow Chemical Co., the 10th U.S. Circuit Court of Appeals found that federal law grants the nuclear industry certain protections from tort liability and plaintiffs cannot seek damages under more lenient state laws.

Specifically, a three-judge panel of the Denver appeals court said the district court erred in instructing the jury that the plaintiffs were not required to establish actual injury to their properties or a loss of use of their properties. Under the federal Price-Anderson Act, which established specific tort liability protections for the nuclear industry, plaintiffs must show that a “nuclear incident” occurred by demonstrating “loss of or damage to property or loss of use of property,” the court said.

Plaintiffs in the case have filed a motion seeking an en banc hearing.

Several environmental attorneys unaffiliated with the Rockwell case say the 10th Circuit's ruling likely would have some influence on public nuisance torts on greenhouse gas emitters' contributions to global warming. So far, two appeals courts have allowed public nuisance climate change cases to proceed absent a federal law prohibiting them.

The Obama administration intervened last month in one of the cases, American Electric Power Co. Inc. et al. vs. State of Connecticut et al., which is on appeal to the U.S. Supreme Court, asserting that the U.S. Environmental Protection Agency, rather than the courts, should address whether plaintiffs can sue emitters of greenhouse gases. In that case, the 2nd U.S. Circuit Court of Appeals allowed a suit filed by a coalition of states, environmental groups and New York City to proceed against several of the nation's largest coal-burning utilities.

The 10th Circuit “is now one of several federal circuit courts that have evaluated the question of whether state court nuisance claims are precluded by federal regulations,” said William F. Stewart, a partner at Nelson Levine de Luca & Horst L.L.C. in Blue Bell, Pa., who specializes in climate change litigation.

He said it adds to the 4th U.S. Circuit Court of Appeals' decision in State of North Carolina vs. Tennessee Valley Authority, the 5th Circuit's decision in Ned Comer et al. vs. Murphy Oil USA Inc. et al. as well as Native Village of Kivalina vs. Exxon Mobil Corp., which is pending before the 9th Circuit.

Though not specifically a global warming case, plaintiffs in North Carolina vs. TVA successfully argued that emissions from the TVA's power plants reach North Carolina airspace, where they damage human health and the environment, creating a “public nuisance” under the state's common law.

After failing to assemble a quorum of judges for an en banc hearing, the 5th Circuit recently reinstated Comer, which was filed by a group of Gulf Coast property owners who allege that oil and electric power companies' emissions “added to the ferocity of Hurricane Katrina” by contributing to global warming (BI, March 2 and March 8).

In Kivalina, a group of Eskimo villagers allege that 24 oil, energy and utility companies' greenhouse gas emissions have caused Arctic sea ice to diminish, threatening native fisheries.

In an e-mail, Richard Faulk, a partner at Gardere Wynne Sewell L.L.P. in Houston, who represents several chemical, refining, manufacturing and insurer organizations in AEP, said the 10th Circuit's decision “underlines the importance of traditional public nuisance principles in all contexts of nuisance litigation, including climate change litigation. Most importantly, the court stresses that, to be actionable, the interference with one's enjoyment of property must be "substantial' and "unreasonable.' The court also noted that the fact-finder "must weigh the gravity of the harm and the utility of the conduct causing that harm.'”

“This is a far cry from the 2nd Circuit's decision in Connecticut vs. AEP, which held that claims could proceed even if the interference was "trifling.' The standard applied by the 10th Circuit properly notes that a defendant's contribution to creating the nuisance must be significant, and that the interference must be more than speculative; it must be supported by scientific proof, not irrational fears and concerns about risks to health, safety or welfare,” Mr. Faulk wrote.