Since publication of EPA’s non-hazardous secondary material (NHSM), boiler maximum achievable control technology (boiler MACT) and commercial and industrial solid waste incinerator (CISWI) rules earlier this year, EPA has quietly issued written assurances to companies that some of their waste streams can be classified as fuel rather than waste, thus placing incineration of the materials under the less stringent boiler MACT rule rather than the CISWI rule. Industry representatives welcome this flexibility, but environmentalists criticize the use of informal letters that were not provided for in the February 7 rules. To date, it is known that EPA has informed Waste Management, Inc. that its “SpecFUEL”, derived from sorted and processed municipal solid waste, can be classified as a fuel (August 22); Wellons Energy Solutions that it can use processed turkey poult litter as fuel in its cogeneration power plants (March 11); Vexor that plastics, paper and cardboard could be burned along with industrial wastes such as soy-based inks and chemicals as a substitute for coal (May); and We Energies that it could burn fuel made from coal ash processed to remove contaminants and combined with virgin coal (June 16). Challenges to the NHSM, boiler MACT and CISWI rules all remain pending in the D.C. Circuit Court of Appeals.