The problem was with the wire that is coated with a rubbery feeling PVC coating that was found to be toxic to gliders causing neurologic symptoms, seizures and often death of the gliders. This wire is usally the black coated wire with 1/2 x 1 inch rectangular spaces. Some manufacturers wire is safe, others are not but it is difficult to identify who made the wire once it is a part of a cage.
Martin's cages now sells the same 1/2 x 1 inch rectangular wire that is Powder Coated and safe for gliders.
The PVC pipes used for the stealth and other glider wheel stands and also for building many homemade cages is NOT dangerous for gliders. The same type of pipes are used in plumbing and water supply lines for drinking water as well.