Canon has published an advisory that some people may suffer an allergic reaction to Zinc bis used in the front rubber grips of the EOS Rebel T4i. While Canon has not received any reports of injury or allergic reactions yet, they are warning that, “in rare cases when this substance comes into contact with skin, allergic skin reactions may develop. In addition, if eyes are rubbed after contact with the substance, symptoms, such as red eyes, may develop.”
Free repair service for affected cameras will be available by mid July 2012: the rubber grips will be replaced.
To see if your camera is affected, read the advisory at: Canon.