Are Lithium Batteries Dangerous Goods? (Yes — Here's Why)

Yes — lithium batteries are dangerous goods. Under the UN Model Regulations and every modal rulebook built on them (IATA DGR, IMDG Code, ADR and 49 CFR), lithium-ion and lithium metal batteries are classified as Class 9 — Miscellaneous Dangerous Goods. They ship under one of four UN numbers and, depending on size and configuration, are either fully regulated or fall under the lighter Section II rules. None of those paths make them "not dangerous goods."

The confusion is understandable. A phone, a laptop or a cordless drill does not feel like hazmat. But the cell inside it can enter thermal runaway, and a thermal-runaway fire in an aircraft cargo hold is one of the scenarios aviation regulators fear most. That is exactly why the rules exist — and why a small consumer battery and a pallet of bare cells are treated on the same regulatory spectrum.

Why lithium batteries are Class 9

Class 9 is the catch-all for substances and articles that present a transport hazard but do not fit Classes 1 through 8. Lithium batteries sit here because their hazard is energetic and chemical rather than, say, simply flammable or corrosive. A damaged, short-circuited or defective cell can self-heat, vent flammable gas, and ignite — and once one cell goes, it can cascade to its neighbours. For the wider Class 9 picture and the other eight classes, see the complete guide to UN numbers and hazard classes.

The four UN numbers

Every lithium battery in commerce ships under one of four entries. The first decision you make — which UN number — drives almost everything that follows. Each links to its dedicated lookup page:

• UN3480 — Lithium-ion batteries (standalone). Includes lithium polymer and power banks. The most aggressively regulated of the four because bare cells have caused in-flight fires.
• UN3481 — Lithium-ion batteries contained in equipment or packed with equipment. A laptop with its battery installed ships here.
• UN3090 — Lithium metal batteries (standalone). Non-rechargeable. CR123A and most camera "primary" lithium cells. Forbidden on passenger aircraft above the Section II thresholds.
• UN3091 — Lithium metal batteries contained in or packed with equipment. A smoke detector with a lithium coin cell installed ships here.

Lithium-ion is rechargeable. Lithium metal is not. CR2032 coin cells, the long cylindrical cells in some smoke alarms, and camera batteries marked "Li/MnO₂" are lithium metal. Getting the chemistry wrong on the paperwork is a UN-number misdeclaration — one of the most common and most expensive errors in the entire discipline.

Standalone vs in-equipment vs packed-with

Beyond chemistry, the second axis is configuration. The same battery is treated differently depending on whether it travels alone or with the device it powers:

• Standalone (UN3480 / UN3090) — the battery ships by itself: spare cells, replacement packs, power banks, bulk cells for manufacturing.
• Contained in equipment (UN3481 / UN3091) — the battery is installed in the device it powers.
• Packed with equipment (UN3481 / UN3091) — the battery is in the same package as the device but not installed.

Standalone is the most restricted configuration in every mode. That is why "is this a spare battery or an installed one?" is a question worth answering before you do anything else.

When the lighter Section II rules apply

Whether a lithium battery is fully regulated or eligible for the relaxed Section II of its packing instruction comes down to size and quantity:

• Lithium-ion: cells up to 20 Wh and batteries up to 100 Wh, within the per-package quantity limits, can use Section II.
• Lithium metal: cells up to 1 g lithium content and batteries up to 2 g, within the package limits, can use Section II.

Section II excepts the shipment from the full Shipper's Declaration but still requires the lithium battery mark, the correct UN number on the package, and — for air — the air waybill statement. Above those thresholds, you are in Section IA or IB: full Class 9 dangerous goods, UN specification packaging, hazard label and a complete Declaration. For the full packing-instruction matrix and the 30% state-of-charge rule, read the lithium battery shipping compliance guide.

Common edge cases

• Power banks are UN3480 standalone batteries, not equipment — a frequent and costly misclassification.
• Damaged, defective or recalled (DDR) lithium batteries are forbidden by air under the normal entries and follow dedicated packing instructions PI 908 / PI 909.
• Sodium-ion batteries received their own entries (UN3551 / UN3552) recently and are not lithium — do not file them under a lithium UN number.
• Button cells installed in equipment are still Class 9; a greeting card with a coin cell is technically a UN3091 shipment, though many qualify for Section II relief.

The bottom line

Lithium batteries are always dangerous goods. The only question is how much regulation applies — and that is decided by chemistry (ion vs metal), configuration (standalone, in-equipment, packed-with) and size (Section II vs fully regulated). Get those three calls right and the rest of the rulebook follows in order: UN number → packing instruction → section → marks → documents.

If you ship batteries across modes, the next thing worth understanding is how the four big rulebooks differ. See IATA vs IMDG vs 49 CFR vs ADR for a side-by-side, or use the UN number lookup tool to pull up any of the four lithium entries in seconds.