CTIA asked a federal court yesterday to block San Francisco's new cell phone law, which requires wireless retailers to inform customers about the possible health effects of the devices.

The posters and pamphlets mandated by the city's Cell Phone Right to Know ordinance identify cell phone radiation as a "possible carcinogen."

CTIA wants to stop the law from going into effect, arguing to the court that it violates First Amendment rights and conflicts with federal regulations governing the safety of wireless devices.

"The materials the city would require be posted and handed out at retail stores are both alarmist and false," CTIA public affairs chief John Walls said in a statement, citing FCC standards limiting the amount of radiation that can be emitted by cell phones.

San Francisco scuttled its first attempt to pass the cell phone ordinance after CTIA filed suit against the law last summer. The city passed a set of revised regulations in July, prompting CTIA to again challenge the rules in court.

City Attorney Dennis Herrera criticized CTIA's move, saying the group's suit trivialized the First Amendment and attempted to "keep people in the dark about vital health information."

"I'm disappointed that the wireless industry is so bent on quashing the debate about the health effects of cell phone radiation," Herrera said, arguing that the city has a "vital interest in keeping people informed about health issues."

The city must reply to CTIA's motion by Friday. A hearing on the case is set for Oct. 20.