With the recent scare over BPA’s in plastics, mom had gone through and threw out anything that was bad (except for a few things). Luckily, she always buys stainless steel bowls for me so there was no danger there, at least for me. It seems like most of the danger for plastics was for young children, but pets like kids are sometimes more sensitive to these chemicals than humans.
Another danger lies in the cleanliness of the bowls used to feed us. Plastic is more porous than stainless steel or ceramic bowls and so it captures bacteria and holds onto it more easily. The materials and chemicals used to create plastic bowls can also be affected when you microwave it or apply heat to it. Go Fetch Gifts wrote a nice article about the safety of plastic bowls and how it’s probably safer to switch to stainless steel or ceramic/porcelain. When purchasing ceramic or porcelain bowls, make sure the decoration or paint used on the bowl is lead-free. Check out Go Fetch Gifts second blog entry on using stainless steel, they talk about kitty acne and probably causes related to plastic bowls.
Also remember no matter what, you must clean your pets bowls regularly! Stainless steel bowls are easy to clean, just use a soft rag or sponge and regular dish soap. It doesn’t need any bleach or harsh abrasive materials, these things can actually damage or change the structure of the dish, so stay away from them. With hard to clean, caked on messes, just soak the bowls in dish soap and warm water until it softens.