Researchers say the practice of "dabbing" marijuana may produce cancer-causing chemicals. How much do you know about “dabbing”? The latest trend in marijuana consumption, researchers now say, produces carcinogenic substances. Dabbing uses highly potent marijuana concentrates that are vaporized on a special dabbing rig, similar to a glass water pipe. However, unlike a traditional pipe, dabbing rigs use a small heated surface, called a nail, typically made of glass, metal, or ceramic.