What changed
IMDG Amendment 42-24 became mandatory on 1 January 2026. Biochar shipped as UN 1361 is now Class 4.2, self-heating, and the UN N.4 test can no longer exempt it. Special Provision 978 replaced SP 925 after too many “exempt” cargoes caught fire in containers. Char must travel in UN-approved packaging; bulk loose in a container is not accepted.
The four requirements of SP 978
| Requirement | What the rule says | What it means on site |
|---|---|---|
| Conditioning | Weather unpacked for at least 14 days under cover in open air, or steam and cool after pyrolysis, pack under inert gas and rest 24 h | Two weeks of covered, ventilated storage, or a cooled nitrogen-blanketed filling system |
| Temperature | Pack only at or below 40 °C on the day of packing | Measure char at the fill point, bag by bag |
| Records | Declaration states production date, packing date and packing temperature | Every bag traceable to both dates and a measured temperature |
| Stowage | ≥30 cm headspace; stacks ≤1.5 m, or blocks ≤16 m³ with 15 cm gaps | Fewer bags per container: budget freight per tonne accordingly |
Weathering is a storage problem
Fourteen days of output has to sit somewhere, under cover, in low heaps, temperature-monitored and rotated first-in, first-out, because piled char can self-heat while it weathers. The alternative, cooling and packing under nitrogen with a 24-hour rest, swaps floor space for process equipment.
How much char waits 14 days?
| Line size | kg/h dry char | 14 days, t dry | t wet at 30% moisture | Approx. m³ stored |
|---|---|---|---|---|
| BDV-50 | 50 | 17 | 24 | 70 |
| BDV-150 | 150 | 50 | 72 | 210 |
| BDV-500 | 500 | 168 | 240 | 690 |
| BDV-1000 | 1,000 | 336 | 480 | 1,370 |
Continuous 24 h operation at a wet bulk density of 350 kg/m³; at 250 kg/m³ volumes are 40% larger.
The 40 °C reading has to be real
An air reading in the shed, or one spot-check a day, does not describe what went into each bag. A probe at the fill head, logged against each bag ID and time, puts a record behind the figure on the declaration, along with the packing date and, from your batch system, the production date.
Questions we are asked
Road transport? ADR and RID still allow some test-based exemptions inland, but a container at the port gate must meet the sea rules.
Northern Ireland? Almost every tonne leaving the island, or moving between NI and GB, crosses the Irish Sea. Treat the sea rules as the baseline.
Bulk bags? Packaging must be UN-approved for Class 4.2; carriers differ on what they accept.
Cost? Beyond packaging and lower load per container, carriers apply dangerous goods surcharges; Hapag-Lloyd has announced USD 250 per container on charcoal.
Shipping readiness checklist
- Every batch has a recorded production date.
- Covered, open-air storage for 14 days of output, or a cooled inert-gas packing route.
- Stored piles are temperature-monitored and rotated first-in, first-out.
- Char temperature measured at the fill point and logged for every bag.
- Packaging UN-approved for Class 4.2 and accepted by your carrier.
- Container plan leaves 30 cm headspace within the 1.5 m or 16 m³ limits.
- Your declaration can be filled in straight from your records.
Cool it, measure it, record it
Our QSM Quench, Soak & Mix Chamber brings char down to ≤40 °C in the same pass as nutrient charging. BDV logs temperature, moisture and mass at the fill head for every bag, so your declaration comes straight from the record.
Read next: Biochar dMRV: what registries expect
Sources
- Britannia P&I, Carriage of charcoal and other carbon, UN 1361 and 1362
- Burgoynes, Updated IMDG Code requirements for the carriage of charcoal
- Hapag-Lloyd, New IMDG regulation: mandatory dangerous goods declaration for charcoal (December 2025)
- Biochar Europe, IMDG Amendment 42-24: what biochar shippers must do
General information, not legal or dangerous goods advice. The IMDG Code is the authoritative text: confirm classification, packaging and declaration with your carrier and a qualified dangerous goods adviser.