Why Do Stone Crates Need Fumigation? What Gets Held Is the Wood, Not the Stone
Granite is a mineral and sits outside plant quarantine. What gets held at the destination port is the wood around it. Here is what ISPM 15 actually covers, when a mark is compliant, why no phytosanitary certificate can be issued, and five questions to ask before you book.
What does ISPM 15 actually cover, the wood or the stone?
ISPM 15 regulates wood, not stone. Granite is a mineral and falls outside plant quarantine entirely; no port officer inspects a slab for pests. What gets held is whatever wood holds the slab: the crate, the pallet, the dunnage, the wedges. The standard is titled Regulation of Wood Packaging Material in International Trade, issued under the IPPC, and it covers solid wood packaging from about 6mm upward. So the thing to arrange before shipment is not the 30mm slab, it is the frame underneath it. Get that backwards and every later question goes to the wrong party: nobody issues a phytosanitary certificate for granite, and only the packaging supplier can answer for the wood. In the containers we ship, when a destination port comes back to us for documents, what it asks for is the mark and the voucher on the packaging.
There are three treatment routes. Why look at heat treatment first?
Three routes: HT (heat treatment), MB (methyl bromide fumigation) and DH (dielectric heating). HT means holding the core of the wood at a minimum of 56°C for 30 continuous minutes in a kiln or chamber; the timber comes out dry and goes straight into the warehouse. MB is dosed against a temperature table, sealed, then aerated, which adds two process steps and needs its own slot in the schedule. DH works, but the equipment is not widespread and few plants can take it on. The practical reason to start with HT: the EU does not accept MB, so one HT line serves Europe and other markets without keeping two sets of packaging. On our five-day lead time, heat treatment runs alongside production; fumigation has to be booked separately, and that is the step that slips when a vessel is closing.
That mark on the crate — what makes it compliant?
Three things: what the mark says, where it sits, and the wood itself. The mark is the IPPC wheat ear set inside a rectangular border: the ear on the left, the country code CN joined to the producer code by a hyphen at the upper right, the treatment code HT, MB or DH underneath, and a vertical line between the ear and the data. It must appear on at least two opposite faces, permanent, legible and not transferable; a printout taped on does not count. The third item is the one buyers miss: treated wood still has to be bark-free, and a squared bearer with bark left on can be rejected even with a valid mark. One more layer: in China the mark is applied by enterprises authorised by customs, not by the exporter, so the number on the crate traces back to that authorised plant.
What certificate do I need, and why can no phytosanitary certificate be issued?
It cannot be issued, because that certificate was never meant for wood packaging. A phytosanitary certificate covers plants and plant products: nursery stock, seeds, grain, fresh fruit. Manufactured wood is not on that list. Wood packaging self-certifies instead. The mark states that the wood was treated; the treatment voucher states who applied that mark, when, and by which method. What a buyer calls a fumigation certificate is, in practice, that voucher plus photographs of the mark on the crate. So do not ask a supplier to issue a phytosanitary certificate; you will get either a vague answer or an unrelated document. Ask whether the treatment voucher travels with the shipping documents, and which two faces carry the mark. One correct question here saves a round of correspondence later.
When can packaging skip treatment completely?
A crate built from plywood needs no treatment and no mark. The exemption covers panels that have been glued, heated or pressed: plywood, particleboard, fibreboard, OSB, veneer, plus wood wool, chips and sawdust. None of them can still carry a pest. There is a catch, though. If a plywood crate is stiffened with a solid-wood bearer or brace, that piece needs treatment and its own mark once it is over 6mm. The test is simple: look for any part sawn from a log. Our Maple Red G562 polished slabs run 30mm, about 81 kg per square metre at 2.7 t/m³, and a 20ft container holds 346 m², so a full load lands at almost 28 tonnes — net stone weight, before crates and bearers, and already at the payload ceiling of a 20ft container. The load-bearing structure cannot be skipped, which is exactly why solid bearers still turn up inside plywood crates.
The container is held at the port — what now, and what should I ask before ordering?
First establish whether the cargo or the packaging is being held. Stone itself is rarely the problem; in the cases we have handled it was an unclear mark, a missing voucher or bark left on the timber. The order that works: send photographs of the mark and the treatment voucher to the broker at the destination port first, to prove the treatment exists. If the packaging genuinely does not comply, have it re-treated or replaced locally and accept the time and cost. Re-export is the last resort, charged per container. Five questions at quotation stage cost far less than five at the port, and whatever storage and re-documenting the delay adds up to after arrival is yours to carry.
| What to ask | Why it matters | What to check |
|---|---|---|
| Is the code HT, MB or DH | The EU does not accept MB and counts it as untreated; HT and DH are both accepted | The code inside the mark |
| Which two faces carry the mark | One face alone counts as no mark at inspection | Crate photos before loading |
| Is any bark left on the timber | A marked bearer with bark can still be rejected | End grain and edges of the bearers |
| Does the voucher travel with the documents | The mark self-declares; the voucher is the proof | Voucher number matches the plant code on the mark |
| Will the destination accept MB | Acceptance varies by country; a wrong call means re-working the container | Ask the broker at the destination port first |