McDonad's as well as five other chains will soon be in trial with the California Supreme Court for breaching California's Proposition 65, which requires consumers to be warned about carcinogenic products.
"In independent laboratory tests commissioned by PCRM (Physicians Committee for Responsible Medicine), 100 grilled chicken items from McDonald’s, Burger King, Chick-fil-A, Chili’s, Applebee’s, Outback Steakhouse, and TGI Friday’s were all found to contain PhIP, one of a group of carcinogens called heterocyclic amines (HCAs)."
PhIP is linked to breast cancer with its DNA-damaging characteristics as well as hormonal activity. Thus far, only Burger King has settled the lawsuit by posting warning signs in its California locations.
see article here: http://www.pcrm.org/newsletter/nov10/phip.html