Filling up on waste: plastics clean up the environment by consuming other industries' byproducts.

We can't deny it: Plastics are products of the chemical industry. That's enough to make them automatically suspect to many ordinary citizens. It's also enough to make plastics perpetual targets of scare stories from environmentalists and the popular media. But here's a new twist: So accustomed are we to allegations that plastics emit, exude, or exhale something unpleasant into the soil, water, or air that we may have overlooked contrary evidence that plastics are taking waste products out of the environment.

Take blast-furnace slag left over from steelmaking. It has to be disposed of somewhere. At least some of it finds a useful purpose in the form of hollow microspheres and "mineral fibers" used as fibers in plastics. Plastics also help dispose of the solid waste that results when smokestack "scrubbers" remove sulfur compounds from stack gases. The calcium sulfate byproduct, a synthetic gypsum, serves as a flame-retardant filler - just like natural gypsum does.

But none of that compares with the surprising information sent to me recently by Robert D. Swain, president of Chroma Corp., a color-concentrate formulator in McHenry, Ill. Bob has fought tirelessly for years against the tide of condemnation and misinformation regarding "heavy metal" pigments. Bob's newest revelation is that the process of manufacturing these allegedly hazardous pigments actually consumes thousands of tons of highly toxic industrial waste, turning it into beneficial and environmentally innocuous products. Here's what Bob says about cadmium: "In the zinc manufacturing process a toxic byproduct is generated that contains elemental cadmium. Over 2 million lb of that toxic waste is converted into 3 million lb/yr of cadmium pigment - an insoluble, nontoxic form that is useful to society. If the environmentalist/regulator is successful in choking off the use of cadmium pigments, how would they propose to deal with the 2 million lb of toxic waste from the zinc industry? From an ecological point of view, we should all be promoting widespread use of these pigments."

Bob makes a similar argument about lead pigments: "The pigments industry. uses 10 million lb/yr of recycled elemental lead in the manufacture of 30 million lb of lead chromate and lead molybdate. They are converting soluble, toxic elemental lead into insoluble, nontoxic forms. Shouldn't the environmentalist, the regulator, and the media be looking for ways to help us encourage their use?"

You mean plastics actually help clean up the environment? Stop the presses!