The Supreme Court heard arguments on Tuesday over whether a truck driver fired for failing a drug test after using a “wellness product” which was falsely advertised to be free of THC may sue the manufacturer under a federal racketeering law.

A majority of the justices seemed ready to side with the driver, Douglas Horn, on the narrow question before them: whether he could satisfy the law’s requirement that he had been injured in his “business or property.” But that is not the only hurdle Mr. Horn must clear to win under the law, the Racketeer Influenced and Corrupt Organizations Act, or RICO.

“There’s a whole lot more to RICO than simply damages,” Justice Sonia Sotomayor said, indicating that any victory Mr. Horn might win would be provisional. If the court rules for him, it will return his case to the lower courts for further proceedings.

The case, Medical Marijuana Inc. v. Horn, No. 23-365, started after Mr. Horn came across an article in High Times, a magazine that covers the business and culture of marijuana, concerning a “wellness product” called Dixie X. It was said to be rich in CBD, a component of hemp that does not produce the high associated with marijuana, but to contain “0 percent THC,” the psychoactive ingredient in cannabis.

Knowing he faced random drug tests as a commercial truck driver, Mr. Horn said he conducted additional research, watching YouTube videos, visiting the manufacturer’s website and calling the company’s toll-free phone number. All confirmed that the product contained no THC.

After using Dixie X, Mr. Horn failed a drug test and was fired. Suspecting that the product was to blame, he bought another bottle and had it tested. The testing company found that it contained THC and refused to mail it back to Mr. Horn, fearing penalties under federal drug laws.