Class 4 dangerous goods cover flammable solids, self-heating substances, and materials that react dangerously with water. They move regularly through chemical manufacturing, metal processing, agriculture, and industrial supply chains — and by air, they carry some of the tightest restrictions in the IATA Dangerous Goods Regulations (DGR).
Unlike ocean freight, air transport of Class 4 goods is governed by strict packing instructions, aircraft-type limitations, and state/operator variations that change the shipment plan before a single box is packed. This case study covers how our team handled a Class 4 export from China by air for an international industrial
customer.
Customer Background
An overseas industrial customer needed to export a Class 4 dangerous goods consignment from China by air freight. The requirement wasn’t just “find a flight” — it was a shipper needing:
- Correct UN classification and Packing Group determination
- IATA DGR-compliant documentation
- An airline with active Class 4 acceptance for the relevant UN
number - Coordination across origin handling, customs, and destination clearance
Because liability for correct classification and documentation sits with the shipper — not the airline — getting this right upfront was non- negotiable.
Project Challenges
1. Classification comes before anything else Class
4 splits into three distinct divisions, each with different air transport implications:
4.1 – Flammable Solids Ignite through friction, heat retained from manufacturing, or contact with sparks.
4.2 – Substances Liable to Spontaneous Combustion Self-heat and ignite without an external ignition source — a serious concern in a sealed aircraft hold.
4.3 – Dangerous When Wet React with moisture to release flammable gases; humidity exposure during ground handling is a real risk factor.
Before booking, we reviewed the Safety Data Sheet (SDS), confirmed the UN number and proper shipping name, and determined the Packing Group (I, II, or III) — because Packing Group drives permitted quantities, packaging performance level, and whether the shipment can move at all.
A critical checkpoint many shippers miss: several Class 4 entries are forbidden on passenger aircraft entirely and can only move as Cargo Aircraft Only (CAO). Confirming this early avoided a routing dead-end later in the process.
2. Airline and state/operator variation checks
Class 4 acceptance isn’t uniform across carriers. We verified:
- Which airlines currently accept the specific UN number and Packing Group
- State variations (origin/destination country restrictions) and operator variations (carrier-specific DG exclusions) published in the IATA DGR
- Whether the shipment required CAO routing or could move on a combi/passenger aircraft
- NOTOC (Notification to Captain) handling requirements at origin
This groundwork is what prevents a shipment from being accepted at booking and then rejected at the warehouse — a common and costly failure point for Class 4 air cargo.
3. Documentation built to IATA DGR standard
For air shipments, the core document is the Shipper’s Declaration for Dangerous Goods, prepared to IATA DGR format — not a generic dangerous goods form. Our team handled:
- SDS review and cross-check against the declared UN number
- Shipper’s Declaration for Dangerous Goods, completed by IATA Category 6-trained staff
- UN packaging specification verification (marks matching the tested packing group)
- Commercial and export documentation aligned with customs and airline requirements
Every one of these documents is a liability point for the shipper. Errors here — not gaps in airline screening — are the leading cause of DG shipment delays and rejections.
Our Class 4 Air Freight Solution
Step 1: Cargo Assessment Reviewed product characteristics, confirmed UN number, Class/Division, and Packing Group, and checked destination-country import restrictions before quoting a routing.
Step 2: Logistics Planning Selected a carrier with active Class 4 acceptance for this UN number, confirmed CAO vs. passenger aircraft eligibility, and built the documentation package to IATA DGR standard.
Step 3: Shipment Management Coordinated origin acceptance, NOTOC handling, and customs clearance through to delivery, with the Shipper’s Declaration matched to the physical packaging at every handoff.
Why This Matters
Class 4 dangerous goods by air fail for the same few reasons, repeatedly: wrong Packing Group, missing CAO routing, or a Shipper’s Declaration that doesn’t match IATA DGR format. None of these are airline screening failures — they’re shipper-side classification and documentation gaps, and they’re entirely preventable with the right process upfront.
That’s the difference professional DG handling makes: not just moving the cargo, but making sure it’s classified, packaged, and declared correctly before it ever reaches the tarmac.