A Washington group filed suit against seven national restaurant chains, saying their California stores must warn that their grilled chicken has carcinogens.

The Physicians Committee for Responsible Medicine, a non-profit preventive medicine and research group, said Thursday it filed the suit in California Superior Court in Los Angeles against the chains, claiming they violated the state's requirement that businesses post a warning if they expose patrons to carcinogens. The group wants such a warning included on the restaurants' menus.

The group said grilled chicken sold by the chains contains "PhIP," a carcinogenic compound included on California's list of cancer-causing substances. The group said it sent chicken samples to a lab for testing and they were found to contain the carcinogen.

The suit named restaurant parent companies of McDonald's, Burger King, T.G.I. Friday's, Applebee's, Chick-fil-A, Chili's and Outback Steakhouse.

Copyright 2006 by United Press International