DOT Compliance

What Can and Cannot Share a Lab Pack Drum

September 2026·10 min read

One hazard class per outer packaging. That is the rule that governs most of lab packing, it is one sentence long, and almost every mistake I have seen comes from someone not knowing it or thinking their situation is the exception.

Here is what the regulations actually say, and where the traps are.

What a lab pack is

A lab pack is a combination packaging: small inner containers of waste chemical, cushioned in absorbent, inside one outer drum or box. It exists because shipping a hundred half-full reagent bottles individually would be absurd.

49 CFR 173.12(b) is the authorising paragraph. It excepts these packages from the usual specification packaging requirements when the waste is moving for disposal or recovery by highway, rail or cargo vessel.

Only nine classes are eligible

Class 3 and Divisions 4.1, 4.2, 4.3, 5.1, 5.2, 6.1, 8 and 9. That is the list in 173.12(b)(1).

Explosives, gases and radioactive material are not on it. Class 1, Class 2 and Class 7 cannot be lab packed at all, which is why a partly full aerosol can and a lecture bottle are two different problems.

The five things that can never go in

173.12(b)(3) names them:

The inhalation hazard one is worth dwelling on, because it is not obvious from the bottle. Whether a material is poisonous by inhalation is assigned in Column 7 of the hazardous materials table through special provisions 1 through 4, which correspond to Hazard Zones A through D. You cannot tell by looking. You have to check the entry.

Across the whole 172.101 table there are 316 UN numbers prohibited on those grounds, and 231 of them sit inside classes that are otherwise perfectly lab packable. Those are the ones that catch people: 219 in Division 6.1 and 9 in Class 8, materials that look routine on the shelf and are not.

One class per outer packaging

49 CFR 173.12(b)(2)(ii): each outer packaging may contain only one class of waste material.

Not one compatible group. Not one chemical family. One class. Flammables with flammables, corrosives with corrosives, oxidizers on their own.

When two or more chemically compatible wastes in the same class share a drum, you may use a generic n.o.s. description from the table rather than naming every chemical, which is the practical reason lab packing works at all.

Same class is not the same as compatible

This is the second rule, and it comes from EPA rather than DOT. 40 CFR 264.316(d) prohibits incompatible wastes from sharing an outside container.

Class 8 is where this bites. Acids and bases are both Class 8. Putting them in the same drum satisfies the DOT one-class rule and violates the EPA one, because Appendix V to 40 CFR part 265 lists alkaline caustics and acids as incompatible groups 1-A and 1-B, with the consequence listed as heat generation and violent reaction.

The Appendix V groups are worth reading once. Six pairings, each with the reason:

That last one is the reason oxidizers get their own drum even when nothing else in the room is an oxidizer.

Container limits

From 173.12(b)(2)(i) and (ii):

Authorised outers are a UN 1A2, 1B2 or 1N2 metal drum, a 1D plywood drum, a 1G fiber drum or a 1H2 plastic drum at Packing Group III performance or better, a double walled 4G fiberboard box with a 3 mil liner at PG II, or a 11G or 11HH2 IBC with a 6 mil liner at PG II.

Two specifics: Division 4.2 Packing Group I must use steel or plastic drums at PG I performance, and bromine pentafluoride and bromine trifluoride may not go in fiberboard at all.

The cyanide and acid exception

Lab packs get an exception from the vehicle segregation tables. Under 49 CFR 173.12(e), they are excepted from 174.81(d), 176.83(b) and 177.848(d) if they are blocked and braced at least 1.2 metres (4 feet) horizontally from incompatible material and loaded at least 100 millimetres (4 inches) off the floor. The vehicle may not carry any Class 1 explosives, Class 7 radioactive material, or uncontainerized hazmat.

Waste cyanides and waste acids on the same vehicle have hard numbers attached: the cyanide may not exceed 2 kilograms net per inner packaging or 10 kilograms per outer, or 2 litres and 10 litres for solutions. The acids must be in lab packs or in single packagings authorised in Column 8B, not exceeding 208 litres.

Land disposal restrictions

Lab packs can use an alternative to the subpart D treatment standards under 40 CFR 268.42(c), but only if the pack meets 264.316 or 265.316, is incinerated under part 264 or 265 subpart O, and contains none of the codes in Appendix IV to part 268.

That exclusion list is short enough to memorise: D009, F019, K003, K004, K005, K006, K062, K071, K100, K106, P010, P011, P012, P076, P078, U134 and U151.

D009 is mercury, and it is the one that shows up in real lab packs most often.

Checking a specific material

The determinations above are all per-entry, and doing them from memory is how mistakes happen. Our lab pack segregation tool takes a UN number or shipping name and returns whether it can be lab packed, which pack family it belongs in, the container limits, and the specific prohibition if there is one. It covers all 2,480 entries in the 172.101 table.

If you need the waste codes rather than the shipping side, the waste code finder asks the two questions that actually decide it, whether the material is spent and whether it is a sole active ingredient, and shows the condition attached to every candidate code.

The short version

One hazard class per drum, and then split further wherever Appendix V says the contents are incompatible. Check the table entry before assuming a Class 6.1 or Class 8 material is eligible, because inhalation hazard and PG I are not visible from the label. Absorbent sufficient to absorb everything, 4 litres for glass, 205 kilograms gross. And keep mercury out of anything headed for the alternative land disposal standard.

Have a lab cleanout coming up and no idea what is in the cabinet? Unknowns are the expensive part of any lab pack job. Find environmental services in your area or read about waste profiling and characterization.