If you have purchased a tufted area rug with a glued on fabric backing, chances are it may have a foul smell, like burnt rubber or gasoline. This is due to the latex used to laminate the cloth backing to the back of the carpet. Natural latex can smell stronger than synthetic latex, and can smell anywhere from a couple of weeks to lasting for years!
The other, more damaging, problem with a rug with this odour is that the off-gassing fumes can actually discolor hardwood, laminate, linoleum and wall to wall carpeting permanently. Also, this odour will not wash or clean out of the rug. Believe me we've tried! To avoid this issue, do yourself a favour and buy an area rug that is hand knotted or machine made where the back of the rug is not covered with a fabric. Keep in mind, not all fabric-backed rugs have this problem. Use your nose before making a purchase, there should be NO SMELL of rubber!