San Francisco adopted an ordinance requiring retailers to provide consumers with certain information about radiofrequency (RF) radiation from cell phones. CTIA – The Wireless Association sued, arguing that the ordinance violated the First Amendment and was preempted by FCC regulation. The district court upheld part of the ordinance and struck down part, and both sides appealed. In a very brief opinion issued in September 2012, the court of appeals held that the ordinance violates retailers’ First Amendment rights because the information that it requires retailers to convey is not “purely factual and uncontroversial.” San Francisco filed a petition for rehearing en banc with the court of appeals, which was denied. We represented the Environmental Working Group (EWG) and Public Citizen as amici curiae in support of San Francisco on appeal.