UN3090 lithium metal batteries table entry.

Where UN3090 sits in the table

Unlike UN3480 and UN3481, which are lithium ion entries, UN3090 covers lithium metal and lithium alloy batteries. The table row has special provisions 388, 422, A54, packaging section 185 in all three of columns 8A to 8C (173.185), stowage category A and other provision 156. Column 9A is "Forbidden", which 172.101(j)(1) defines as meaning the material may not be offered for transportation or transported in the applicable mode.

The practical consequence is the label. 172.101(j)(4) says a package offered by aircraft that is filled with a material forbidden on passenger-carrying aircraft but permitted on cargo aircraft only shall be labelled with the CARGO AIRCRAFT ONLY label specified in 172.448.

The full row from the eCFR copy of the table, current through October 29, 2026 and read November 2, 2026, is below. Every value is copied from 49 CFR 172.101; the last column is the regulation's own explanation of the column.

The 172.101 row, column by column

How the regulation defines the hazard class

173.140 says, abridged: "miscellaneous hazardous material (Class 9) means a material which presents a hazard during transportation but which does not meet the definition of any other hazard class. This class includes any material which has an anesthetic, noxious or other similar property which could cause extreme annoyance or discomfort to a flight crew member so as to prevent the correct performance of assigned duties, and any material that meets the definition in 171.8 for an elevated temperature material, a hazardous substance, a hazardous waste, or a marine pollutant."

Special provisions on this entry, in the rule's words

Column 7 does not explain itself; each code is defined in 172.102. These are the definitions as printed in the eCFR text for the codes listed on the row. Where a provision ends with a list of conditions that this page does not reproduce, it says so.

• 388: Lithium batteries containing both primary lithium metal cells and rechargeable lithium ion cells that are not designed to be externally charged, must meet the following conditions (the listed conditions continue in the rule).
• 422: When labelling is required, the label to be used must be the label shown in § 172.447. When a placard is displayed, the placard must be the placard shown in § 172.560.
• A54: Irrespective of the quantity limits in Column 9B of the § 172.101 table, a lithium battery, including a lithium battery packed with, or contained in, equipment that otherwise meets the applicable requirements of § 173.185, may have a mass exceeding 35 kg if approved by the Associate Administrator prior to shipment. When approved by the Associate Administrator and shipped in accordance with this special provision, the special provision must be noted on the shipping paper.

What else to know about this entry

Because lithium metal cells are measured by lithium content, not Watt-hours, the smaller-battery exception in 173.185(c)(1) reads differently. (c)(1)(ii) says the lithium content may not exceed 1 g for a lithium metal cell or 2 g for a lithium metal battery. (c)(1)(iv) lets a highway-or-rail-only shipment go to 5 g per cell and 25 g per battery if the outer package is marked "LITHIUM BATTERIES—FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL."

(c)(1)(iii) requires the outer package to be marked "PRIMARY LITHIUM BATTERIES—FORBIDDEN FOR TRANSPORT ABOARD PASSENGER AIRCRAFT", "LITHIUM METAL BATTERIES—FORBIDDEN FOR TRANSPORT ABOARD PASSENGER AIRCRAFT", or one of the other listed marks, or labeled with a CARGO AIRCRAFT ONLY label, except when the batteries are packed with or contained in equipment in quantities not exceeding 5 kg net weight.

Special provision 388 begins: "Lithium batteries containing both primary lithium metal cells and rechargeable lithium ion cells that are not designed to be externally charged, must meet the following conditions", and the conditions follow in the rule. Special provision A54 allows more than 35 kg on a cargo aircraft only with prior approval from the Associate Administrator.

Air quantity limits and a worked example

Columns 9A and 9B give the largest net quantity allowed in one package: column 9A for passenger-carrying aircraft or passenger-carrying rail car, column 9B for cargo aircraft only. 172.101(j) says "Forbidden" means the material may not be offered for transportation or transported in the applicable mode, and that the limit is net unless stated otherwise. For UN3090 the row shows Forbidden in column 9A and 35 kg in column 9B.

Worked example, 30 kg net in one package. Passenger aircraft or rail car (column 9A, Forbidden): Forbidden. Cargo aircraft only (column 9B, 35 kg): within 35 kg. The calculator above applies the same comparison to the quantity you type.

Highway placard check

Class 9 is on Table 2 of 172.504(e) as CLASS 9 (see 172.504(f)(9)). 172.504(f)(9) says "a CLASS 9 placard is not required for domestic transportation, including that portion of international transportation, defined in 171.8 of this subchapter, which occurs within the United States. However, a bulk packaging must be marked with the appropriate identification number on a CLASS 9 placard, an orange panel, or a white square-on-point display configuration as required by subpart D of this part."

Vessel stowage and the ERG guide

Column 10A gives category A (the material may be stowed "on deck" or "under deck" on a cargo vessel or on a passenger vessel). Column 10B lists 156. Code 156 in 176.84: For lithium batteries transported in accordance with 173.185(f) or for purposes of disposal or recycling, stowage category C applies. These apply to shipments by vessel and have no effect on a truck-only move.

The Emergency Response Guidebook 2024 numerical index lists UN3090 under Guide 138, titled "Substances - Water-Reactive (Emitting Flammable Gases)". 172.101 itself does not list ERG guide numbers; the guide number comes from the PHMSA guidebook. The guide is for first responders during the initial phase of an incident and is not a shipping-paper or compliance document.

What this page does not do

It reproduces the table row and the regulation text it points to, and applies the air-limit and 1,001 pound placard comparisons to numbers you enter. It does not classify a product, pick a packing group, decide which table row applies to your shipment, or replace the packaging sections the row points to (the 173 sections in columns 8A to 8C), the marking, labelling and shipping paper rules in part 172, or hazmat training. Hazardous materials employees must be trained; that decision and the shipping description belong to a trained person. The eCFR header for 172.101 links an amendment published at 91 FR 49310 (August 4, 2026); confirm that the version you rely on includes the latest changes. In an emergency call 911 and the emergency response telephone number on the shipping paper.

Sources

Sources opened and read November 2, 2026. Regulation text was read from the eCFR API, which publishes the current Code of Federal Regulations.

• 49 CFR 172.101, Hazardous Materials Table (eCFR text current through October 29, 2026; read November 2, 2026)
• 49 CFR 172.102, Special provisions (read November 2, 2026)
• 49 CFR 172.504, General placarding requirements (read November 2, 2026)
• 49 CFR 173.140, hazard class definitions (read November 2, 2026)
• 49 CFR 176.84, Other requirements for stowage, cargo handling, and segregation (read November 2, 2026)
• 49 CFR 173.185, Lithium cells and batteries (read November 2, 2026)
• PHMSA: Emergency Response Guidebook 2024 English PDF, numerical index (read via the Internet Archive capture of October 31, 2026; read November 2, 2026)