A coconut shell carbon plant in Indonesia loaded 20 tonnes of activated carbon for a US west coast buyer. The booking went in as general cargo, the container was packed, and the carrier then asked for the self-heating test report. There was none for this batch. The cargo was re-declared under UN 1362, the space was released, and the shipment waited eleven days for a slot that accepts class 4.2.
Activated carbon is not an inert black powder in the way talc or carbon black is. It adsorbs oxygen, and adsorption releases heat. In a sealed box with no airflow, that heat has nowhere to go.
One report decides the whole booking
The question is not whether activated carbon is dangerous. It is whether this batch passed the self-heating test. Everything downstream — booking class, documents, stowage, lead time — follows from that single answer.
| Result | How it ships | What the file needs |
|---|---|---|
| Self-heating test passed | General cargo, ordinary dry container | The test report for this batch, kept with the shipping instructions |
| Test failed, or none available | UN 1362, class 4.2, DG booking and DG stowage | DG declaration, DG packing certificate, MSDS, approved stowage |
Three things that sink the booking
- A report for a different batch. Carbon from a different kiln run, or a report older than the production date, does not cover this cargo. Carriers check the batch, not the product name.
- A wet liner. Moisture is what starts the reaction. A torn inner liner, a damp bag or a sweated container floor turns a passed batch into a live risk in transit.
- Neighbours in the wrong place. Oxidisers and acids must not share the box, and the stow should sit away from machinery space heat. This is stowage planning, not luck.
Booking early is part of the technical spec
- Test first, book second. Sampling and the self-heating test need time; ask the lab before you ask for space, and keep the sampling record.
- Seven days is a working minimum to have the report reviewed and the general-cargo booking confirmed.
- Ten to fourteen days is the realistic window for a DG booking on a US west coast service, plus the approved stowage plan.
- On Southeast Asian loadings in the hot season, ask for a slot away from the engine room rather than accepting whatever is left.
The loading checklist, eight steps
- Sample per batch and send it for the self-heating test before the booking is confirmed.
- Match the report to the batch number and the production date, then file both.
- Declare the cargo: general cargo with report, or UN 1362 with a DG declaration. Do not leave the choice to the booking clerk.
- Check every bag and inner liner for tears, damp patches and intact sealing.
- Inspect the container: dry floor, no holes, no residue from the previous cargo, no smell of solvent.
- Load with a clear air channel and no bags pressed against the side walls for the full height.
- Seal the container and photograph the seal, the door, the stow pattern and the batch labels together.
- Send the document set with the shipping instructions, so the carrier has it before the vessel closes.
The document set
| Document | Why it is asked for |
|---|---|
| Self-heating test report | Decides general cargo or class 4.2, and must match the batch |
| MSDS | Shows the carrier what the cargo is before it accepts the space |
| DG declaration and packing certificate | Only when the cargo ships as UN 1362 |
| Packing list with batch numbers | Lets the report, the bags and the container be tied together |
| Loading photographs | The only record of liner condition and stow pattern if a claim arrives |
Three answers that do not survive a check
"We have always shipped it this way" is not a test report. "Nobody asked last time" is not a defence when a container is found hot at the terminal. "The buyer said it is fine" moves the risk to you without moving the responsibility.
A plain note from the desk: for this cargo the report is not paperwork, it is the booking. Without it you are not choosing a container, you are choosing a delay.
Send the batch, the port pair and the production date on WhatsApp before the next booking, and we will tell you which test is needed, how long the space will take, and what goes into the file.