Special Provision 188: Lithium Battery Limits, Testing, and Packaging

Special Provision 188 lets you ship small lithium cells and batteries as “excepted” from most dangerous goods rules, provided each cell and battery stays under a set energy or lithium-content threshold, passes UN 38.3 design testing, and travels in packaging that carries the lithium battery handling mark. The Special Provision 188 lithium battery requirements skip the full Dangerous Goods Declaration and much of the hazmat paperwork, but the batteries are still Class 9 hazardous materials, and a mistake can produce civil penalties above $100,000 per violation.

Which Batteries and UN Numbers SP 188 Covers

SP 188 comes out of the United Nations Model Regulations and has been folded into the air, sea, and ground frameworks. It applies to lithium ion (rechargeable) and lithium metal (non-rechargeable) cells and batteries, sorted by four UN numbers:

UN 3480: lithium ion batteries shipped alone
UN 3481: lithium ion batteries packed with or installed in equipment
UN 3090: lithium metal batteries shipped alone
UN 3091: lithium metal batteries packed with or installed in equipment

The split between “packed with” equipment and “contained in” equipment is not cosmetic. A laptop with the battery installed ships differently from a box holding a loose battery next to an unconnected device, and packing instructions and quantity limits change with the configuration.¹

Energy and Lithium-Content Thresholds

Qualification for SP 188 comes down to one question: does every individual cell and battery in the package sit within the limits? A single unit over the threshold pushes the whole shipment into full dangerous goods regulation.

Lithium Ion

Lithium ion is measured in watt-hours (Wh). Each cell can be up to 20 Wh, and each battery (multiple cells assembled) up to 100 Wh.² A phone battery is roughly 10 to 15 Wh, a laptop battery 40 to 60 Wh, both well inside the ceiling. Power tool packs and e-bike batteries frequently break 100 Wh and cannot use SP 188.

If the Wh rating is not printed on the battery, multiply voltage by ampere-hours. For milliampere-hours, divide by 1,000 first. A pack rated 11.1 V and 4,400 mAh works out to 11.1 × 4.4 = 48.84 Wh. Any battery made after December 31, 2015 must have the Wh rating on the case, so checking newer units is usually quick.³

Lithium Metal

Lithium metal is measured in grams of lithium. A cell is capped at 1 gram; a battery at 2 grams aggregate.² Common AA lithiums and coin cells sit well under the limit. Industrial lithium metal units used in military and medical gear often do not.

Higher Limits for U.S. Ground-Only Shipments

If your package stays on trucks or trains inside the United States from origin to destination, federal rules give you much more room: lithium metal cells up to 5 grams, lithium metal batteries up to 25 grams, lithium ion cells up to 60 Wh, and lithium ion batteries up to 300 Wh. The outer package must be conspicuously marked “LITHIUM BATTERIES—FORBIDDEN FOR TRANSPORT ABOARD AIRCRAFT AND VESSEL.”⁴

This is where mid-sized batteries like power tool packs and e-bike batteries can travel without full dangerous goods treatment. The trade-off is absolute: the moment such a package touches a plane or a vessel, the marking is a lie and the standard SP 188 thresholds apply. Misrouting a ground-only-marked package onto an aircraft is a serious violation.

UN 38.3 Design Testing

Before any lithium cell or battery type enters transportation, it must pass the tests in the UN Manual of Tests and Criteria, Part III, subsection 38.3.⁵ The tests simulate altitude changes, temperature swings, vibration, mechanical shock, and external short circuits. Fail any one and the design cannot be offered for transport at all.

You test the design, not each individual unit. Once a design passes, production units qualify if manufactured under a documented quality management program.

Manufacturers and every distributor down the chain must be able to hand over a UN 38.3 Test Summary on request to buyers, carriers, and regulators. The summary names the cell or battery type, the testing lab, and the results. Button cells installed in equipment (including circuit boards) do not need the test summary.⁴

Under U.S. rules, the manufacturer keeps the full test report on file for as long as that design is offered for transport, plus one year after the design is discontinued.⁴ If you import batteries from overseas, confirming the summary exists and is accessible is your job as the shipper. Carriers ask for it, and its absence stops shipments.

Packaging, Marking, and Shipping Papers

Packaging

Loose cells and batteries (not installed in a device) go into inner packaging that fully encloses them. Each unit needs short-circuit protection: non-conductive sleeves, tape over the terminals, or individual plastic bags. The inner packaging goes into a strong outer package that can survive a 1.2-meter drop in any orientation without cells shifting into contact, sustaining damage, or escaping.³ Gross package weight cannot exceed 30 kg.

No third-party test certificate is required for the drop test. It’s a functional requirement, not a certification, which means you should actually drop a sample rather than assume a standard shipping box will hold up.

Markings

Each outer package carries the lithium battery handling mark: a bordered rectangle with the battery symbol, the applicable UN number, and a phone number for more information. The mark must be at least 100 mm × 100 mm, with a reduced 100 mm × 70 mm version allowed on packages too small for the standard size.¹ The UN number on the mark must be at least 12 mm high.

On U.S. ground-only shipments using the higher weight limits, text markings must be at least 6 mm high on packages up to 30 kg and at least 12 mm high on heavier ones.⁴

Button cells in equipment get relief. Packages containing only button cells installed in devices do not need the lithium battery mark. Packages with no more than four cells or two batteries installed in equipment are also exempt, provided the consignment contains no more than two such packages. Button cells in a device that also holds larger cells or batteries do not count toward those package limits.

Shipping Papers

A full Dangerous Goods Declaration is not required, but you must include a statement confirming the shipment was prepared per SP 188 or the applicable modal equivalent. For air, the air waybill has to say the shipment contains lithium batteries prepared per the relevant packing instruction, Section II.

Extra Rules for Air Shipments

Air carries the heaviest overlay on top of SP 188. ICAO Technical Instructions and IATA Dangerous Goods Regulations govern the details, mostly in Packing Instructions 965 through 970, Section II.⁶

State of Charge

Lithium ion batteries shipped by air without equipment must be at a state of charge no higher than 30% of rated capacity. Starting January 1, 2026, the 30% cap also applies to lithium ion batteries packed with the equipment they power, expanding a rule that previously covered only batteries shipped alone.⁷ Batteries already installed in equipment are not subject to the SOC limit.

Passenger Aircraft

Lithium metal batteries shipped alone (UN 3090) are forbidden on passenger aircraft. Lithium ion batteries shipped alone (UN 3480) under Section II are likewise cargo-only.⁶ Batteries packed with or installed in equipment (UN 3481 and UN 3091) may travel on passenger aircraft under Section II, subject to package weight limits.

One Package Per Consignment

Air shipments under Section II of PI 965 (lithium ion alone) and PI 968 (lithium metal alone) are limited to one package per consignment. You cannot combine multiple Section II packages into an overpack for these categories.⁶ Batteries packed with or contained in equipment have their own per-package weight limits, but not the one-package restriction.

Maritime and U.S. Ground

The IMDG Code incorporates SP 188 directly for sea transport. Batteries meeting every SP 188 condition do not need to be offered to the vessel operator as Class 9 dangerous goods and skip the full marking, labeling, placarding, and shipping paper requirements of the Code.⁸ The 30 kg package limit applies. For U.S. ground, 49 CFR 173.185 provides equivalent exceptions, and the higher ground-only thresholds apply only when the package can be guaranteed to stay off aircraft and vessels.⁴

Batteries That Cannot Ship Under SP 188

Damaged, defective, or recalled lithium batteries are excluded from excepted shipping, regardless of size or energy rating. The thermal-runaway risk is too high for SP 188 packaging to address.

If a battery is swelling, leaking, showing heat damage, or subject to a recall, do not ship it under SP 188. Under U.S. rules, damaged or defective batteries travel only by highway, rail, or vessel (no air) and must be packaged to Packing Group I, the most stringent standard. Each battery goes into individual non-metallic inner packaging surrounded by non-combustible, electrically non-conductive, absorbent cushioning, then into a metal, wooden, or rigid plastic box or drum that meets UN performance testing at the PG I level. The outer package must be clearly marked to identify damaged or defective lithium batteries inside.⁴

Batteries returned for recycling or disposal are not automatically treated as damaged, but the shipper must assess fire hazard before choosing a shipping method. Any sign of degradation and the damaged-battery rules apply.

Training

Anyone who classifies, packages, marks, or handles paperwork for lithium battery shipments needs hazardous materials training. Under U.S. rules, that means four components: general awareness of hazmat identification, function-specific training for the actual tasks performed, safety training covering emergency response and workplace hazard protection, and security awareness.⁹ Refresher training is required at least every three years, and air shipments trigger additional IATA-specific training. Excepted status does not exempt anyone from training.

Penalties

Civil penalties for knowingly violating federal hazmat transportation rules run up to $102,348 per violation. If the violation causes death, serious injury, or substantial property destruction, the ceiling rises to $238,809 per violation.¹⁰ Each improperly prepared package can count as a separate violation, so a single mislabeled pallet can generate penalties in the millions.

Criminal liability attaches when violations are knowing or willful. Prison exposure runs up to five years, and up to ten years if a release causes death or bodily injury.¹¹ Undeclared lithium batteries on aircraft draw the most enforcement attention, and enforcement in this area has been trending up.

1
IATA. Battery Guidance Document – Transport of Lithium Metal, Lithium Ion and Sodium Ion Batteries
2
UNECE. Special Provision 188 for Shipping Lithium Batteries
3
PHMSA. Lithium Battery Guide for Shippers
4
eCFR. 49 CFR 173.185 – Lithium Cells and Batteries
5
United Nations Digital Library. Recommendations on the Transport of Dangerous Goods Manual of Tests and Criteria
6
IATA. Lithium Battery Shipping Guidelines
7
IATA. Fact Sheet – Lithium Batteries
8
PHMSA. Interpretation Letter Regarding Special Provision 188 of the IMDG Code
9
eCFR. 49 CFR 172.704 – Training Requirements
10
eCFR. 49 CFR 107.329 – Maximum Penalties
11
Office of the Law Revision Counsel. 49 USC 5124 – Criminal Penalty