A New Jersey woman whose diet consisted almost exclusively of canned tuna for five years can sue a tuna fish producer over the mercury poisoning she allegedly suffered from, the U.S. Supreme Court said Monday.

Deborah Fellner sued Tri-Union Seafoods LLC under the New Jersey Product Liability Act for failing to warn her of the dangers of eating the company’s canned albacore tuna. She claimed that the Tri-Union Seafoods tuna products that she ate from 1999 to 2004 contained methylmercury and other harmful compounds which caused her injury.

California-based Tri-Union Seafoods LLC, who market their products under the “Chicken of the Sea” brand, said the company was not responsible for her claimed illness, arguing that the U.S. Food and Drug Administration does not consider canned tuna fish worthy of mercury warnings to consumers. The company referenced a 2005 letter the FDA sent former California Attorney General Bill Lockyer* that said state-mandated mercury warning labels were pre-empted by federal law.

The law suit was thrown out by U.S. District Court Judge Dennis Cavanaugh, but the 3rd U.S. Circuit Court of Appeals reinstated the class action.

“State law is not pre-empted whenever an agency has merely ‘studied’ or ‘considered’ an issue; state law is pre-empted when federal law conflicts with state law,” 3rd U.S. Circuit Senior Judge Walter Stapleton wrote for the appeals court.

In response to the ruling of the 3rd U.S. Circuit Court of Appeals, Tri-Union Seafoods asked the U.S. Supreme Court to review the case and the justices have now allowed the appeals court ruling to stand. The U.S. Supreme Court has not commented on their decision.

* Lockyer was trying to sue three tuna producers (one of them being Tri-Union Seafoods) for not complying with California’s Proposition 65. According to Proposition 65, businesses must provide “clear and reasonable” warnings before exposing people to known carcinogens or reproductive toxins.