What Is a Fumigation vs. Heat Treatment Certificate — the Difference for Importers
A pallet arrives with a stamp you cannot read, and the paperwork calls the treatment “fumigation” while your border agent says only heat treatment passes. The fumigation vs heat treatment certificate difference decides whether that pallet clears or sits in a bonded yard at your cost. Both methods are approved under ISPM 15, and both leave a mark on the wood, but they behave differently in the real world. This guide explains how each treatment works, what each certificate records, how the mark reads for each method, and how to handle the question of which countries accept which.
Quick Answer
Heat treatment heats the wood to at least 56 degrees Celsius at its core for 30 minutes, and the stamp carries the code HT. Fumigation exposes the wood to a gas, usually methyl bromide, coded MB. Both are approved under ISPM 15, but many destinations restrict fumigation. The certificate is the provider’s record of the treatment, while the stamp on the wood is what inspectors check.
How Heat Treatment and Fumigation Differ in Practice
Heat treatment uses temperature to kill pests inside the wood, and fumigation uses a gas to do the same job. The practical differences show up in speed, residue, environmental rules and how widely each treatment is accepted.
Heat treatment
The provider places the wood in a kiln or heat chamber and raises the core temperature to at least 56 degrees Celsius, holding it for a continuous 30 minutes. Probes at the coldest point in the load confirm that every piece reaches the target. Nothing is left on the wood afterwards, so it can be handled straight away and no aeration period is needed. The standard also recognises dielectric heating, coded DH, which uses microwave-type heating and suits smaller batches.
Fumigation
The provider seals the wood under gas-tight conditions and releases the fumigant, holds the exposure for a set time at a set temperature, then ventilates the load. Methyl bromide, coded MB, has been part of ISPM 15 since the beginning, and sulphuryl fluoride, coded SF, joined in the 2018 revision. Methyl bromide depletes the ozone layer and falls under the Montreal Protocol, which is why a growing number of countries restrict or refuse wood treated with it. The wood also needs ventilation before people handle it.
Why the difference matters to you
You care about the method because your own country decides which methods it accepts. Heat treatment is the option that almost every destination accepts. Fumigation carries more conditions, and some of them change. A pallet that was fine for one buyer last year can fail at your border today, and the supplier’s pallet maker will not be the one paying the storage bill.
What Each Certificate Records
The certificate is the treatment provider’s written record, and its contents differ by method. A heat treatment certificate records that a temperature was reached and held. A fumigation certificate records that a gas was applied at a stated dose, temperature and exposure time.
Heat treatment certificate
Expect the provider’s name and registration number, the date of treatment, the treatment code HT, the core temperature reached, the time held at that temperature and a description of the wood packaging treated, usually with quantities or reference numbers. A record that gives no temperature or time is a weak record.
Fumigation certificate
Expect the provider’s name and registration number, the date, the fumigant used, the dose, the exposure period, the temperature during treatment and the description of the goods. Some destinations expect the fumigation certificate to accompany the shipment, and a few also expect a stated exposure time. Confirm what your border authority wants before shipment, because the certificate has to support the mark, not replace it.
Not the same as a phytosanitary certificate
Neither document is a phytosanitary certificate. That certificate is a government document for plants and plant products, issued by the exporting country’s National Plant Protection Organisation. A correctly marked wood pallet does not normally need one for the wood itself. A supplier who offers a phytosanitary certificate instead of a mark may be trying to cover for packaging that was never treated.
What the Marking Should Show for Each Method
The mark on the wood shows the IPPC symbol, the country code, the treatment provider’s number and a treatment code. The code is the piece that tells you which method was used: HT for heat treatment, DH for dielectric heating, MB for methyl bromide and SF for sulphuryl fluoride. The IPPC text of ISPM 15 sets these out.
Reading a mark from India
A mark on wood treated in India carries the country code IN, a number assigned by India’s plant protection authority to the treatment provider, and the method code. Indian treatment providers are approved through the Directorate of Plant Protection, Quarantine and Storage, whose procedures appear at ppqs.gov.in. If the stamp shows only IN and a number, with no method code, the mark is incomplete.
Marks that do not count
A “DB” note means the wood was debarked, and debarking alone does not satisfy ISPM 15. Some stamps add “KD” for kiln-dried, which describes moisture content and does not prove a phytosanitary treatment. Stamps that are painted on, smudged, applied to only one board of a crate, or missing the provider number should be treated as failed marks until proven otherwise.
Which Countries Accept Which Treatment
Acceptance varies by destination and changes over time, so treat any country list from a supplier or a blog as a starting point and confirm with your own plant health authority. Heat treatment is the safest choice, because it is accepted almost everywhere the standard applies.
The pattern is consistent, even though the details move. Many countries have restricted or banned methyl bromide for wood packaging, and some accept it only under conditions. Australia and New Zealand publish their own import conditions on top of ISPM 15, and Australia’s BICON database is the place to check them. Some countries have exemptions for wood of local origin moving between neighbouring states, and those exemptions do not help a shipment from India.
The practical rule is simple. Ask your national plant protection authority which treatments it accepts for wood packaging from India, get the answer in writing, and put it in the purchase order. Write “heat treated, marked HT” if you want to avoid the question altogether.
Container Fumigation Is a Separate Question
Some destinations also require the container itself, or the cargo, to be fumigated, and the paperwork for that is called a fumigation certificate too. That treatment applies to the container and its contents, and it is separate from the treatment of the wood packaging. If a document is described as a fumigation certificate, check whether it covers the wood packaging, the container or the cargo. The wrong document for the wrong job will not clear the goods, however official it looks.
What to Ask Your Supplier Before Loading
Ask for the treatment method, the provider’s name and number, a copy of the treatment certificate and photographs of the stamps on at least two sides of each wooden item. Compare the provider number on the certificate with the number on the wood, and confirm that the code matches the method you agreed. Ask what happens to the packaging between treatment and loading, because wood that sits beside untreated timber can be re-infested.
On every StoneCrest International order, the pre-shipment logistics check confirms correct packing, protection and labelling before the container is sealed, and the buyer sees pre-shipment photographs before it departs. That is the moment to read the stamps on the wood. Under the NexaCrest Order Standard, one named contact stays accountable from order confirmation through to delivery, so a packaging question goes to one person. You can see how each stage works on the NexaCrest How We Work page.
Frequently Asked Questions
What is the difference between a fumigation certificate and a heat treatment certificate?
A heat treatment certificate records that the wood reached at least 56 degrees Celsius at its core for 30 minutes, and the stamp carries the code HT. A fumigation certificate records that a gas such as methyl bromide was applied at a stated dose, temperature and exposure time, and the stamp carries MB or SF. Both support the mark on the wood.
Is heat treatment better than fumigation for wood packaging?
For most importers, yes. Heat treatment leaves no chemical residue, needs no ventilation period and is accepted by almost every destination that applies ISPM 15. Fumigation with methyl bromide faces restrictions in a growing number of countries because of its effect on the ozone layer. Confirm your own country’s rules before you agree the method.
What does HT mean on a wood pallet stamp?
HT stands for heat treatment. The stamp shows the IPPC symbol, the country code, the treatment provider’s number and the code HT. It confirms that the wood was heated to the approved temperature for the approved time by a provider registered with its national plant protection authority. It does not confirm that the wood stayed pest-free afterwards.
Do I need a certificate if the pallet already has an ISPM 15 stamp?
The stamp is what border inspectors check, and a correctly marked pallet normally enters without a separate document for the wood. Many importers still ask for the provider’s treatment certificate, as a record for their files and for insurers or customers. Match the provider number on the certificate to the number on the stamp.
Can a pallet be re-treated if the stamp is wrong or missing?
Only an approved treatment provider can treat and mark wood packaging, and the destination authority decides what happens to non-compliant wood on arrival. The options usually include treatment, re-export or destruction at the importer’s cost. Fixing the stamp before the container leaves India is far cheaper than fixing it at your border.
If you are planning a shipment from India and want to see how packing checks, pre-shipment photographs and follow-up after delivery fit together, start with the NexaCrest How We Work page. It sets out each stage of an order and what you receive at each one, so the packaging question is answered before the container is sealed.