Offshore drilling workers come under federal wage law, not California state law, said the U.S. Supreme Court Monday in a unanimous ruling that overturns a federal appeals court ruling and denies an oil rig worker salary for time spent on standby.

The Outer Continental Shelf Lands Act extends federal law to the subsoil and seabed of the Outer Continental Shelf and all its attachments, according to the Supreme Court’s ruling in Parker Drilling Management Services Ltd. v. Brian Newton.

Mr. Newton worked for Houston-based Parker on drilling platforms off California’s coast, with 14-day shifts involving 12 hours per day on duty and 12 hours per day on standby, during which he could not leave the platform, according to the decision delivered by Justice Clarence Thomas.

Although he was paid “well above” the California and federal minimum wages for his time on duty, he was not paid for his standby time, according to the ruling.

Mr. Newton filed a class action in California state court alleging violations of several California wage-and-hour laws and related state court claims, including that California’s minimum wage and overtime laws, which required Parker to compensate him for the time he spent on standby.

After Parker removed the case to U.S. District Court in Los Angeles, the parties agreed the Parker’s platforms were subject to the OCSA. Their disagreement centered on whether California laws applied.

Applying precedent established by the 5th U.S. Circuit Court of Appeals in New Orleans, the District Court ruled the Federal Fair Labor Standards Act of 2018, not California state law, applied, and ruled in Parker’s favor.

The 9th Circuit vacated the ruling and remanded the case, ruling state law was applicable.

The Supreme Court agreed with the District Court. “Although this is a close question of statutory interpretation, on the whole we find Parker’s approach more persuasive,” said the ruling.

“Our pre-OCSLA decisions made clear that the Federal Government controlled the OCS in every respect, and the OCSLA reaffirmed the central role of federal law on the OCS,” said the ruling.

“Given the primacy of federal law on the OCS and the limited role of primacy of federal law on the OCS and the limited role of state law, it would make little sense to treat the OCS as a mere extension of the adjacent State law, where state law applies unless it conflicts with federal law,” the ruling said.

Mr. Newton’s interpretation of the law “would render much of the OSCLA unnecessary,” said the ruling, in overturning the 9th Circuit’s decision.

Attorneys in the case could not immediately be reached for comment.

In another unanimous ruling, earlier this month the Supreme Court ruled against an employer who waited too long to object that a regulatory complaint did not match a claim in subsequent litigation.