August 17, 2021

Detailed Guidance on the Part 241 NHSM Regulations

The criteria to determine whether nonhazardous secondary materials (NHSM) are solid wastes when used as fuels or as ingredients in combustion are codifed in 40 CFR Part 241. To assist regulators and the regulated community in understanding the nature of these self-determination provisions, EPA published an NHSM guide for waste and non-waste determinations. Released in May 2021, the guide goes through each step of a non-waste determination, discusses the two types of NHSM petitions, and provides links to additional guidance and associated CAA compliance requirements.

When combusting an NHSM, the material is considered a solid waste unless determined to be a non-waste under Part 241. The determination has far-reaching implications as it impacts the applicable standards under the CAA. Units combusting an NHSM that is a solid waste are subject to CAA section 129 and would be regulated as commercial and industrial solid waste incinerators (a.k.a. CISWIs). On the other hand, units combusting only NHSM that are not solid waste per Part 241 are subject to CAA section 112 and would be regulated as boilers or similar units. To better demonstrate how to make an NHSM fuel self-determination, the agency included a flowchart walking the user through the criteria to consider. Depending on how the questions are answered, the user ends with a clear “material is a waste” or “material is not a waste” answer.

EPA’s guide also lays out how the petitioning process works when self-determination is not practical. Two methods are provided to petition the agency for an NHSM determination. The first, in §241.3(c), allows for petitions to be sent to the EPA regional administrator or OLEM assistant administrator for a one-off determination. The agency considers if the NHSM is a legitimate fuel per §241.3(d)(1) and meets other criteria in §241.3(c)(1). This petition involves a notice-and-comment process but does not result in a change to the Part 241 regulations.

The second type of petition, detailed in §241.4(b), is sent to the EPA administrator for a categorical non-waste determination. This approach is useful when seeking a nationally applicable determination. While this approach also involves a notice-and-comment rulemaking process, if the petition is approved, then the appropriate changes will be promulgated in §241.4(a).

Additional information on NHSM is available, as well as resources for understanding CAA standards in the waste management industry.


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