The biggest wireless industry trade group is suing the City of Berkeley, California to stop a requirement that cell phones come with radiation warnings.

The Berkeley City Council last month passed an ordinance requiring cell phone retailers to provide the following notice to all customers who buy or lease phones:

To assure safety, the Federal Government requires that cell phones meet radio frequency (RF) exposure guidelines. If you carry or use your phone in a pants or shirt pocket or tucked into a bra when the phone is ON and connected to a wireless network, you may exceed the federal guidelines for exposure to RF radiation. This potential risk is greater for children. Refer to the instructions in your phone or user manual for information about how to use your phone safely.

CTIA- The Wireless Association, which represents carriers and suppliers, sued in US District Court yesterday, saying the "required disclosure... impermissibly abridges CTIA’s members’ First Amendment rights," that it is "preempted by federal law," and that there is no scientific basis for the warning.

"The Federal Communications Commission ('FCC') implements a mandate from Congress to create a nationwide, uniform set of regulations for wireless communications devices," CTIA wrote. "Pursuant to that mandate, the FCC—consulting with expert federal health and safety agencies and drawing from international standards-setting bodies—has carefully reviewed the scientific studies that have examined cell phones for possible adverse health effects, including health effects from the radio waves—a type of radiofrequency energy ('RF energy')—that cell phones emit in order to function. The FCC has determined, consistent with the overwhelming consensus of scientific authority, that '[t]here is no scientific evidence that proves that wireless phone usage can lead to cancer or a variety of other problems, including headaches, dizziness or memory loss.'"

The FCC's standards are conservative, CTIA wrote, saying that the commission's "exposure limits for RF energy in a general population setting 'are set at a level on the order of 50 times below the level at which adverse biological effects have been observed in laboratory animals.'"

When contacted by Ars, a Berkeley spokesperson responded, "We don’t comment on pending litigation."

San Francisco revoked a similar ordinance in 2013 after losing a court battle to CTIA. But Berkeley isn't giving up. The San Francisco Chronicle reported yesterday: