Frequent Questions

A facility treats groundwater contaminated with a listed hazardous waste by filtering the water through a carbon filter. When the carbon filter is removed from the treatment unit does the derived-from rule or contained-in policy apply to the filter?

When removed from the treatment unit for disposal, the carbon filter is considered a spent material that is subject to regulation as a hazardous waste because it contains a listed hazardous waste. The "derived from" rule (40 CFR §261.3(c)(2)) is not directly applicable because the filter is considered to be an integral part of the treatment process, not a solid waste residue derived from the treatment of a hazardous waste (Memo, Dellinger to Rovers; April 14, 1989 (RCRA Online #11418)). Therefore, when the carbon filter no longer contains the listed hazardous waste, it is not considered to be a hazardous waste (§261.3(f)). According to the contained-in policy, this occurs after a demonstration that the particular medium or debris in question no longer poses a sufficient health threat to deserve RCRA regulation. Once the demonstration is made, the medium or debris in question is no longer considered to "contain" a listed hazardous waste and is no longer regulated (Management of Remediation Waste Under RCRA (EPA530-F-98-026)). 

This document is available at the following URL:

The February 21, 1991, Federal Register provides additional clarification on the regulation of activated carbon units (56 FR 7134, 7200; OSW-FR-91-012). 

Additional guidance regarding the regulation of filters is available in the following guidance documents: 

Memo, Denit to Baker; March 11, 1988 (RCRA Online #11332
Memo, Williams to Heinze; February 11, 1988 (RCRA Online #11325
Memo, Skinner to Suska; July 10, 1985 (RCRA Online #11089
Monthly Call Center Report Question; April 1984 (RCRA Online #12201)
Monthly Call Center Report Question, November 1, 1994 (RCRA Online #13711)

These guidance documents are available in the RCRA Online database available at the following URL:

In addition, it is important to note that this guidance represents clarification of the Federal regulations. Most states are authorized to implement the Federal regulations. We recommend that you also contact your state's implementing agency to acquire additional information on carbon filters. The Office of Resource Conservation and Recovery (ORCR) has compiled a complete list of waste program Web sites maintained by EPA Regional offices and state environmental agencies to help users locate the appropriate agency within their states.

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