In a class action lawsuit against various cell phone manufacturers and retailers of wireless handheld telephones, claiming that cell phones, as currently manufactured, are unsafe to be operated without headsets because they may expose the user to dangerous amounts of radio frequency (RF) radiation, district court's dismissal of the complaint on the ground that the claims are preempted by regulations promulgated by the Federal Communications Commission (FCC) is affirmed where: 1) federal jurisdiction exists over the case whether or not plaintiff is correct that the third amended complaint relates back to the second amended complaint; and 2) plaintiff's claims are preempted by the FCC's RF regulations as allowing juries to determine instead whether those regulations are adequate to protect the public would stand as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress.