LETTERS Incinerator or recycler? Dear Editor: While not stated explicitly, a recent research article by Davis et al. {Environ. Set Technol. 1997, 31, 37) is about the hazardous waste incinerator formerly operated by Marine Shale Processors (MSP) in Amelia, La. This facility has long been engaged in legal batdes with regulatory agencies that have held that the facility essentially produces a hazardous product under the guise of recycling. This legal fight recently culminated in the U.S. Supreme Court refusing to hear MSP's appeal of a ruling by the U.S. Court of Appeals for the Fifth Circuit. The Appeals Court upheld the U.S. EPA finding that this facility basically produced hazardous waste and the ruling of an EPA appeals board that MSP must meet permitting requirements as a hazardous waste incinerator. Having been a part of the efforts by EPA and the U.S. Department of Justice to get MSP to comply with federal and Louisiana laws and regulations, and having had our results cited in the Davis et al. paper, we would like to put their work in perspective. The article strongly implies that MSP operated a modern aggregate kiln and that incinerator residue containing as much as 0.5% lead is suitable for distribution in general commerce as a construction material. We strongly disagree with both of these premises. MSP operated a hazardous waste incinerator without a permit. Their so-called product was routinely tested only for the potential leachability of lead and other toxicants from the material when deposited in a landfill (toxicity characteristic leaching procedure, EPA publication SW-846, Method 1311). We are not aware of any successful testing of MSP product as a construction material. The lead does not seem to serve any useful function and is merely a toxic substance along for the ride. We agree that encapsulation in a silicate matrix that is demonstrably stable over time can be a reasonable
way to immobilize and stabilize some wastes. It is another question entirely whether MSP was able to do this on a regular and consistent basis. Davis et al. base most of their conclusions that the lead in MSP slagged incinerator ash is immobilized on tests of one sample, the most recently prepared sample of those reported. The cited results were tests of the
