Frequent Questions

Do the regulations allow dilution of an ignitable or characteristic waste to remove the characteristic?

No generator, transporter, handler, or owner or operator of a TSDF shall dilute a hazardous waste as a substitute for adequate treatment.

However, dilution of wastes that are hazardous only because they exhibit a characteristic and are subsequently discharged under the CWA or SDWA (e.g., Class I underground injection well) is not impermissible, unless a treatment method other than DEACT is specified.

In all cases, the Agency has determined that for non-toxic hazardous characteristic wastes, it should not matter how the characteristic property is removed so long as it is removed.  Thus, dilution is an acceptable treatment method for such wastes.

Any solid waste is not a hazardous waste if it does not exhibit any of the characteristics of hazardous waste identified in 40 CFR Part 261 Subpart C.  However, wastes that exhibit a characteristic at the point of generation may still be subject to the LDR requirements in Part 268, even if they no longer exhibit a characteristic at the point of land disposal.

Characteristic wastes that are exempt from the dilution prohibition and which are managed and disposed of on-site, are not subject to the full Section 268.7 requirements for waste analysis and record keeping.

References:  40 CFR Section 268.3(a)
40 CFR Section 268.3(b); 55 FR 22520, 22532, June 1, 1990
40 CFR Section 261.3(d)
Monthly Call Center Report Question, October 2002 (RCRA Online #14638)
66 FR 27266, 27269, May 16, 2001
The Hazardous Waste Identification Process
40 CFR Section 268.7(a)(7)

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