FOR MANY YEARS a component of plastic, polyvinyl chlorides (PVCs) have been used in products ranging from construction materials to children's toys, and from mini-blinds to intravenous and blood bags.

Polyvinyl chloride was first discovered in 1835 and was one of the first commercially developed plastics. The white powder is made from 57 percent salt and 43 percent oil. It can be blended with a wide variety of stabilizers, lubricators, softeners, and pigments to make a versatile range of products.

There is increasing evidence that there are hazards associated with this material. One problem is that PVC is partly based on chlorine, which is linked to such highly toxic substances as dioxin. Another problem with PVC is that the additives used in it are frequently toxic. Soft ...