EPA signed a final rule February 21, 2011, that defines which materials burned in combustion units are solid waste and subject to emission standards for incinerators and which are considered fuel. In the rule, the agency expands the definition of “fuels” to include whole scrap tires, resinated wood residuals transferred off-site and abandoned coal refuse. The rule also subjects nonhazardous secondary materials that RCRA defines as solid waste to incinerator standards under section 129 of the Clean Air Act, while materials considered to be fuel will be subject to less strict boiler standards under section 112. The final rule will be effective 60 days after it is published in the Federal Register.