[Home](/)/[Resources](/resources)/DOT Lithium Battery Shipping United StatesLithium Battery # DOT Lithium Battery Shipping Regulations: 49 CFR, UN Numbers, and Watt-Hour Thresholds Under 49 CFR Part 173, DOT classifies lithium batteries as Class 9 hazardous materials and assigns them one of four UN numbers based on chemistry, configuration, and size. Get those details wrong and you face carrier rejection, civil penalties, and potential criminal exposure under 49 USC § 5124. This guide walks through exactly how the classification system works, what the 2020 PHMSA amendments changed, and what your shipping staff must do before any lithium battery leaves the dock. Copy Link[Share on WhatsApp](https://wa.me/?text=https%3A%2F%2Fkrono-labs.com%2Fguides%2Fus-dot-lithium-battery-shipping) At a glance UN Numbers 4 Types (3480 / 3481 / 3090 / 3091) Large Format Threshold \>100 Wh (Li-ion pack) / >20 Wh (cell) SOC Limit — Air ≤30% for standalone Li-ion (UN 3480) Key CFR Citation 49 CFR § 173.185 Training Record Retention 3 years per 49 CFR § 172.704 ## The four UN numbers and what determines which applies ### UN 3480 — Lithium Ion Batteries (Standalone) Applies to rechargeable lithium-ion battery packs shipped separately from any device. Large format triggers when a single cell exceeds 20 Wh or the battery pack exceeds 100 Wh. The 2020 PHMSA rule tightened the standalone battery definition — an installed battery removed for shipping reverts to standalone classification. ### UN 3481 — Lithium Ion Batteries Contained in or Packed with Equipment Covers Li-ion batteries shipped inside a device (contained in equipment) or accompanying a device in the same package (packed with equipment). The equipment context unlocks more relaxed Section II air allowances on IATA DGR. Wh limits still apply — cells >20 Wh or packs >100 Wh are large format regardless. ### UN 3090 — Lithium Metal Batteries (Standalone) Lithium metal (primary, non-rechargeable) batteries shipped without a device. Classification as large format triggers when lithium content per cell exceeds 1 g or per battery exceeds 2 g. Common in medical devices, military hardware, and remote sensing equipment. ### UN 3091 — Lithium Metal Batteries Contained in or Packed with Equipment Lithium metal cells or batteries shipped in or with a device. Subject to 49 CFR § 173.185(c) packaging requirements. IATA DGR Section II allowances apply for small quantities — individual lithium content ≤1 g per cell and ≤2 g per battery. ### State of Charge (SOC) Limit — Air Mode 49 CFR § 173.185(f) and IATA DGR 3.9.2.5 require standalone lithium-ion batteries shipped by air to be discharged to ≤30% of rated capacity before tendering. This applies only to standalone (not in-device) Li-ion batteries shipped by air. Ground and vessel modes do not impose a SOC limit under federal regulations. ### IATA DGR Section IA / IB / II — Air Quantity Limits IATA DGR segments air shipments by quantity. Section II (most relaxed) allows passenger and cargo aircraft for small quantities. Section IB allows cargo aircraft only and applies to larger packs. Section IA (most restrictive) covers high-capacity packs and requires specific operator approval. The applicable section determines the shipper's declaration form, label requirements, and approved aircraft type. ## Classification and shipping compliance process 01 Classify each battery as lithium-ion (rechargeable) or lithium-metal (primary non-rechargeable) — this determines the UN number series (34xx vs 30xx) and the metric used for size classification (Wh vs grams of Li content). 02 Calculate the Watt-hour rating for Li-ion cells and batteries (Wh = nominal voltage × rated capacity in Ah). For Li-metal, measure or obtain certified lithium content per cell and per battery from the manufacturer's data sheet. 03 Assign the correct UN number: UN 3480 (Li-ion standalone), UN 3481 (Li-ion in/with equipment), UN 3090 (Li-metal standalone), UN 3091 (Li-metal in/with equipment). Confirm large vs small format status against the Wh or gram thresholds. 04 Determine shipment mode — ground (49 CFR Part 173), air (49 CFR + IATA DGR), or vessel (49 CFR + IMDG Code). Air mode has the most restrictions. For air, identify whether shipment is passenger aircraft eligible or cargo aircraft only using the IATA DGR section tables. 05 If shipping by air and the batteries are standalone Li-ion, verify and document state of charge at ≤30% rated capacity per 49 CFR § 173.185(f). For large-format air shipments, confirm cargo aircraft only restriction and obtain carrier approval where required. 06 Select compliant outer packaging per 49 CFR § 173.185(b) (small quantities) or § 173.185(c) (large format). Inner packaging must prevent short circuit. Each cell must have individual protection (tape, individual bags, or cell-level protection built in). Outer packaging must pass UN performance tests appropriate to the PG. 07 Prepare shipping papers per 49 CFR § 172.200 — include proper shipping name, UN number, hazard class (Class 9), packing group (if applicable), total quantity, and emergency response information. For IATA DGR air shipments, complete the Shipper's Declaration for Dangerous Goods (two original copies for operator). 08 Apply required marks and labels: the IATA lithium battery mark (required for Section II small quantities by air) and/or the Class 9 hazmat label (required for large-format batteries — cells >20 Wh Li-ion or >1 g Li-metal, batteries >100 Wh Li-ion or >2 g Li-metal). Orientation arrows required if applicable. 09 Ensure all shipping staff who prepare, offer, or handle packages containing lithium batteries complete DOT hazmat training per 49 CFR § 172.704. Training must cover general awareness, function-specific content, safety, and security. Retain training records for each employee for a minimum of three years from training date. ## Frequently asked questions ### What UN number applies to a lithium-ion battery pack shipped separately from the device? A standalone lithium-ion battery pack — meaning it is not installed in a device and not shipped in the same package as a device — is classified as UN 3480. This is the most common scenario for replacement battery packs, power banks, and inventory shipments. If the same battery pack were shipped inside the device it powers, or in the same box as the device with the device, it would instead use UN 3481. The 2020 PHMSA rule clarified that removing a battery from a device for shipment purposes makes it standalone, even if it was originally contained in equipment. ### What is the 30% state of charge requirement and when does it apply? The 30% SOC (state of charge) limit under 49 CFR § 173.185(f) and IATA DGR 3.9.2.5 applies specifically to standalone lithium-ion batteries shipped by air — UN 3480. It requires the battery be discharged to no more than 30% of its rated capacity before tendering to a carrier. It does not apply to lithium-metal (primary) batteries, to Li-ion batteries installed in or packed with equipment (UN 3481), or to ground or vessel shipments. The rationale is thermal runaway risk reduction during flight. Shippers must document SOC compliance; carriers may request evidence of testing. ### Do lithium batteries need a Class 9 hazmat label? It depends on format size. Large-format lithium batteries — Li-ion cells exceeding 20 Wh, Li-ion battery packs exceeding 100 Wh, Li-metal cells exceeding 1 g Li content, or Li-metal batteries exceeding 2 g Li content — require the Class 9 hazmat label on the outer package. Small-format batteries shipped by air under IATA DGR Section II do not require the Class 9 label but must display the IATA lithium battery handling mark instead. Ground shipments of small-format batteries may be excepted from labeling under the small quantity provisions of 49 CFR § 173.185(c)(1). ### Can I ship lithium batteries on a passenger aircraft? It depends on UN number, size, and quantity. Small-format Li-ion batteries (cells ≤20 Wh, packs ≤100 Wh) packed with or contained in equipment (UN 3481) are generally permitted on passenger aircraft under IATA DGR Section II. Standalone small-format Li-ion batteries (UN 3480) may also be permitted on passenger aircraft in limited quantities under Section II. Large-format standalone Li-ion batteries (UN 3480 >100 Wh) are restricted to cargo aircraft only. All standalone Li-ion batteries shipped by air must be at ≤30% SOC. Passenger aircraft carriage of lithium batteries as cargo is separate from what passengers may carry as personal electronics — those are governed by FAA/TSA rules. **Disclaimer:** Educational resource only. Regulatory requirements change. Consult a licensed US attorney, customs broker, or compliance specialist before making decisions. 🇺🇸 US roadmap for your product Every standard, document, and test that applies — free, no account required. 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