In a ruling that may sound the death knell for bringing a medical monitoring suit as a class action, the 3rd U.S. Circuit Court of Appeals has refused to certify claims brought by residents of a small northern Illinois town who say they live in fear of contracting cancer due to chemical dumping from a Rohm & Haas plant.

“Because causation and medical necessity often require individual proof, medical monitoring classes may founder for lack of cohesion,” U.S. Circuit Judge Anthony J. Scirica wrote in Gates v. Rohm & Haas .