Canon USA warns that the front rubber grips on some EOS Rebel T4i units may turn white due to a substance called zinc bis (N,N’-dimethyldithiocarbamate).
According to Canon the substance may cause an allergic reaction in some people, and as a precautionary measure they advise owners of affected cameras to wash their hands with water if they have come in contact with the rubber grip.
It definitely is not the first time this happened. I was allergic to the grip of my 5D classics, which also turned white after a couple of years. It took me six months to figure it out and end my suffering from it.
