In the case of Copperweld Steel Co. v. Industrial Commission of Ohio, the U.S Supreme Court ruled in favor of Copperweld Steel Company, overturning a decision by the Ohio Industrial Commission to award workers' compensation benefits to an employee who had contracted silicosis while working at their plant. The court found that there was insufficient evidence to prove that exposure to silica dust at work caused his disease as he also lived near other industrial plants and railroads which could have contributed towards it. Furthermore, they concluded that even if his employment did contribute towards his illness, under Ohio law this would not be enough for him to qualify for compensation unless it was proven beyond reasonable doubt that such exposure was more than a negligible factor in causing or accelerating his disease.

The dissenting opinion in the Copperweld Steel Co. v. Industrial Commission of Ohio case argued that the majority's decision was a departure from established principles of law and an intrusion into state sovereignty. The dissenters believed that the court overstepped its bounds by interfering with Ohio's ability to regulate local industrial conditions, which they saw as a matter for states' rights rather than federal jurisdiction. They also disagreed with the majority's interpretation of "commerce" under Section 2(a) of National Labor Relations Act (NLRA), arguing it should not include manufacturing processes like those at issue in this case because they are intrastate activities, not interstate commerce subject to federal regulation under NLRA. Furthermore, they contended that even if such activities could be considered commerce within NLRA’s meaning, Congress did not intend for it to preempt state laws governing labor disputes when enacting NLRA.