PEX tubing is a flexible plastic tubing used for plumbing. Has been in use since the '70's and is harmless. The connections used in plumbing the PEX tube are available in brass and plastic products. Due to its strength and flexibility it is a very user-friendly product that is easy to work with. If exposed to freezing temps, it will expand and then contract back to its original size upon warmup, therefore no busted waterlines.
Pex tubing is the process by which a layer of aluminum is sandwiched between two layers of a pipe. Some health risks associated with long term use of this product is environmental pollution due to the toxic substances produced.