Is it normal that i love to eat rubber?

I also like to eat rubber. I always liked chewing rubber bands as a kid (and still do if I can find the ones that smell good). When I was pregnant I got a new hot water bottle - it smelled so good and rubbery that I started to chew on it. soon I was cutting bits off. I ate the whole thing.
The rubbery smell inside bike shops, certain (cheap) shoe shops and car tyre show rooms drives me crazy it smeslls so delicious.
Once, when no-one was looking in a car tyre show room, I licked a tyre and it tasted disgusting (not like the smell at all) - someone informed me later that there is a release agent that tyre manufacturers use to get the tyres out of their molds and it is made of horrible chemicals.
Just recently in a big hardware store, I kept smelling the good rubber smell that I love. I went to that aisle and it was wheel barrow tyres. I bought one and at first I just wanted to smell it, so I kept it in my car. It was soo good. After a while, I started to chew on it a little, and now I have started to break off the little rubbery bits that stick out and I have been chewwing them til they go powdery, then I have to spit it in a bin and get a new bit. I don't know why they smell and taste so good. I think they are made of coal and tar (tar is a known carcinogen), but it is compulsive. I love the smell of tar also - it can often be smelled on jetties and in road works. At least I haven't started to eat the road.