International shipments
Pipeline and Hazardous Materials Safety Administration · Jan 11, 2008 · Reference No. 07-0122
Interprets: 49 CFR § 173.12
Reggie’s quick take
Someone asked whether a waste containing a Packing Group I flammable liquid and a Packing Group II toxic liquid can be described as "Waste flammable liquid, toxic, n.o.s., 3 (6.1), UN1992, PG I" and packaged under § 173.12(b). PHMSA said yes. Section 173.12(b)(3) bars Division 6.1, Packing Group I materials from that option, but here the toxic hazard meets only Packing Group II criteria, so the waste may use paragraph (b). If the toxic hazard were Packing Group I, it could not.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) pertaining to materials prepared in accordance with § 173.12(b). Your questions are paraphrased and answered as follows:
Q1. May a waste material that contains a Packing Group I flammable liquid and a Packing Group II toxic liquid be described as "Waste flammable liquids, toxic, n.o.s., 3 (6.1), UN1992, PG I" and be packaged in accordance with § 173.12(b)?
A1. Yes, the proper shipping description "Waste flammable liquid, toxic, n.o.s., 3 (6.1), UN1992, PG I" appropriately describes the material you describe in your letter and the material may be packaged in accordance with § 173.12(b). Note that § 173.12(b)(3) prohibits a Division 6.1, Packing Group I material from being packaged in accordance with paragraph (b). This applies to a waste material meeting the definition of Division 6.1, Packing Group I, regardless of whether the classification is primary or subsidiary. Because the subsidiary hazard for your material meets the Packing Group II criteria, the material may be packaged in accordance with paragraph (b).
Q2. May a waste material with a primary hazard of Class 3, Packing Group II and a subsidiary hazard of Division 6.1, Packing Group I be packaged in accordance with § 171.12(b) in a drum with the proper shipping description "Waste flammable liquid, toxic, n.o.s., 3 (6.1), UN1992, PG I"?
A2. No, although the proper shipping description appropriately describes the material, it may not be packaged in accordance with § 173.12(b) because the subsidiary hazard, Division 6.1, meets the Packing Group I criteria. See A1.
Q3. "Flammable liquid, toxic, n.o.s. (acetone, dichloromethane), 3 (6.1), UN1992, PG II" is lab packed with "Waste flammable liquids, toxic, n.o.s., 3 (6.1) UN1992, PG I." The material is packaged in a combination packaging. The outer container meets the Packing Group II specification. Does the outer container meet the § 173.12 requirements?
A3. Yes. As provided by § 173.12(b)(2)(i), the packages must be tested and marked at least for the Packing Group III performance level.
Q4. May containers of Sodium (4.3, UN1428, PGI) and Sodium dithionite (4.2, UN1384, PGII) be packaged as a lab pack in accordance with § 173.12(b) using the proper shipping description: Waste water-reactive solid, self-heating, n.o.s, 4.3 (4.2), UN3135, PG I?
A4. Yes.
Q5. May a small container of Paraformaldehyde (4.1, UN2213, PG II) be included in the lab pack with "Waste water-reactive solid, self-heating, n.o.s, 4.3 (4.2), UN3135, PG I" without changing the basic description?
A5. No. The Division 4.1 material must be indicated; that is, "Waste water-reactive solid, self-heating, n.o.s., 4.3 (4.2, 4.1), UN3135, PG I."
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.