In 1976, Mars eliminated red-colored M&M's because of health concerns over the dye amaranth (FD&C Red #2), which was a suspected carcinogen, and replaced them with orange M&M's. This was done despite the fact that M&M's did not contain the dye; the action was purely to satisfy worried consumers. Ten years later, Paul Hethmon, then a student at University of Tennessee, started a joke campaign to reinstate red M&M's that would eventually become a worldwide phenomenon. Red M&M's were reintroduced as a result, and the orange M&M's that had originally replaced them were kept in production. In Europe, red M&M's contain the red dye carmine (E120, cochineal).