On December 1, 2000, U.S. EPA issued the Commercial and Industrial Solid Waste Incineration Rule (CISWI Rule), which established emission standards for CISWI units pursuant to Section 129 of the Clean Air Act (CAA). In response to petitions filed by several environmental groups, U.S. EPA granted a motion for reconsideration and filed a motion for
voluntary remand, which was issued on September 6, 2001.
On February 17, 2004, U.S. EPA solicited comments on several key definitions in the CISWI Rule including “solid waste,” “commercial or industrial waste,” and “CISWI unit.” U.S. EPA then issued the CISWI Definitions Rule on September 22, 2005 after review and consideration of the public comments received.
In the September 22, 2005 CISWI Definitions Rule, a “CISWI unit” was defined as “any combustion unit that combusts commercial or industrial waste (as defined in this subpart).” The CISWI Definitions Rule further defined “commercial or industrial waste” as “solid waste (as defined in this subpart) that is combusted at any commercial or industrial facility using controlled flame combustion in an enclosed, distinct operating unit: whose design does not provide for energy recovery (as defined in this subpart); or is operated without energy recovery (as defined in this subpart).” This definition captured only waste that was combusted at facilities that did not recover thermal energy for a useful purpose from the combustion of the material and therefore restricted the applicability of the CISWI Rule. For example, boilers, process heaters, kilns, and other units burning those types of materials that used the energy from combustion were not CISWI units.