(TNS) — The U.S. Supreme Court rejected a telecommunications industry challenge Monday to Berkeley, California’s requirement that cell-phone retailers warn customers about the possible radiation dangers of holding the phones close to their bodies.

The city’s ordinance took effect in 2016. It requires dealers to notify their customers that the Federal Communications Commission sets radiation standards for cell phones, and that exposure “may exceed the federal guidelines” if users carry their phone in a pants or shirt pocket or tucked into a bra while they’re connected to a wireless network.

Retailers must display the warning on a poster or in a handout flyer, attributed to the city of Berkeley.

Cell-phone companies argued that the ordinance violated their free-speech rights by requiring them to deliver a message with which they disagreed. They made that argument earlier in a successful challenge to a San Francisco ordinance, the first of its kind in the nation, which would have required retailers to give buyers a fact sheet saying the World Health Organization considered cell phones’ emissions a “possible carcinogen,” and showing human silhouettes absorbing radiation.

But federal courts have allowed enforcement of Berkeley’s more modest measure, which is tied to Federal Communications Commission standards. After ordering a lower court last year to reconsider the challenge, the Supreme Court denied further review of the industry group’s appeal Monday without explanation and let the ordinance remain in effect. None of the justices issued a dissenting opinion.

“People have a right to know the truth at the point of sale so that they can properly protect themselves and their families,” said Ellen Marks, director of the California Brain Tumor Association, which supported the measure. She said her organization will campaign for similar laws by cities and states nationwide.

CTIA-The Wireless Association, the industry group that challenged the Berkeley ordinance, said it was disappointed by the court’s action, but noted that the Federal Communications Commission itself declared last week that “no scientific evidence establishes a causal link” between cell-phone use and human illnesses.

After a federal judge and the Ninth U.S. Circuit Court of Appeals in San Francisco refused to block the ordinance, the Supreme Court told the appeals court in June 2018 to reconsider the case in light of the high court’s ruling that month on antiabortion clinics known as “crisis pregnancy centers.”

In striking down a California law that required the clinics to post notices about the availability of low-cost reproductive care, including abortions, a 5-4 majority of the court said the notices violated the owners’ rights by making them follow a “government-drafted script” about a controversial procedure they opposed.

The appeals court reconsidered the cell-phone case and reaffirmed its previous conclusion. Berkeley’s warning is “literally true,” promotes public health and does not require retailers to post messages that violate their beliefs, the court said in a 2-1 decision in July.

“The FCC’s required disclosure is no more and no less than a safety warning” that the city is relaying to cell-phone customers, Judge William Fletcher said in the majority opinion. Dissenting Judge Michelle Friedland said the warning carries a message, unsupported by evidence, that cell phones are unsafe.

In a filing seeking Supreme Court review, CTIA’s lawyers, led by Theodore Olson, a former U.S. solicitor general, said the appeals court ruling invites cities “to burden businesses with an ever-expanding rucksack of compelled disclosure requirements — not to prevent any consumer deception, but to suit their own political, ideological, and normative views on a countless variety of topics.”

The case is CTIA-The Wireless Association vs. Berkeley, 19-439.

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