When you think of allergies, several things come to mind, like peanuts, pets, and pollen. But photography? Strange as it may sound, your choice of digital camera could cause an allergic reaction. Canon has issued a product advisory that warns the rubber grips of some EOS Rebel T4i Digital SLR (EOS 650D/EOS Kiss X6i overseas models) cameras contain a substance that could cause people with sensitive skin to develop a rash or have some other allergic reaction.
Affected models were produced in certain lots between May 31 and June 27, 2012. At issue is the existence of zinc bis, which Canon says isn't used in the production of these cameras, "however the quantity of rubber accelerator used in the affected production lots was slightly higher than usual," and zinc bis could end end up deposited in the grips. Regardless of whether there's an allergic reaction, the rubber grips could turn white after a short period of time, especially in environments prone to high temperatures and high humidity.
To check if your model is affected, flip it over and peek at the serial number. If the sixth digit is a "1" then you may have a unit that is prone to this effect. If it's a "2" or higher, your model is not affected. For those who fall into the former category, Canon is offering to repair or replace the device.
You can find more information on Canon's product advisory page .