Are transporters considered generators when they mix wastes of different DOT descriptions?

No. Transporters who mix wastes of different DOT descriptions are not considered generators of the waste, however, they must comply with 40 CFR Part 262, “Standards Applicable to Generators of Hazardous Waste” (Section 263.10(c)). The transporter does take on some of the responsibilities and duties of a generator when he mixes wastes that are in his custody, including making sure the wastes remain properly manifested in the manner required by Parts 262-263. When transporters combine similar wastes, this act does not “generate” a new waste. It might, however, necessitate a new manifest or an amendment to the manifest when the act of mixing wastes changes the accuracy of the information on the manifest, by altering the container types and/or volumes contained or by changing the chemical or physical nature of the waste, so that the DOT proper shipping name on the original manifest is no longer accurate. If a new manifest is necessary, previous manifests must be attached to, and conveyed with, the new manifest.