What Is Methyl Bromide (MB)? Is It Banned?

Methyl bromide (MB) is a colourless, odourless gas used as a powerful fumigant to control fungi, insects, weeds, nematodes and rodents. It was once standard for treating wood packaging under ISPM 15 before export. Because it depletes the ozone layer, the EU banned it in 2005 and most countries now restrict it to narrow quarantine uses, pushing exporters toward heat treatment instead.

What is methyl bromide?

Methyl bromide is a colourless, odourless gas (chemical formula CH3Br) used as a broad-spectrum fumigant. It penetrates soil, wood and stored goods to kill a wide range of pests, including fungi, insects, weeds, nematodes (roundworms) and rodents. For decades it was used widely in agriculture and international shipping to treat soil, timber and farm produce, preventing pests from spreading across borders.

A wood pallet treated with methyl bromide is stamped “MB” to certify it has undergone this fumigation. This is one of the accepted treatment steps for export wood pallets shipped to other countries.

Why methyl bromide was used on wood pallets

Wood pallets move goods across the world. To stop pests spreading between countries, the timber must be treated under the international ISPM 15 standard, and methyl bromide fumigation was one of the two accepted methods. The treatment protects the ecosystems of importing countries from invasive species hiding in untreated wood.

The MB fumigation process

The downsides of methyl bromide

Human health

Methyl bromide is highly toxic and can cause serious health effects at high exposure. Symptoms include:

• Abdominal pain, headache, dizziness and memory loss.
• Damage to the central nervous system and the respiratory system.
• Skin contact can cause redness, itching and, in severe cases, burns and skin damage.

The environment

Methyl bromide is an ozone-depleting substance. Under the Montreal Protocol it is classified as a Class I ozone-depleting substance. When released into the air it weakens the ozone layer, letting more harmful ultraviolet (UV) radiation reach the Earth’s surface, with serious knock-on effects for health and ecosystems.

Is methyl bromide banned? Bans and exemptions

Methyl bromide is banned or tightly restricted in many countries because of its health and environmental impacts. The European Union banned its use in 2005, save for a few special cases. In the United States, the Environmental Protection Agency phased out most production and import under the Clean Air Act, retaining only narrow exemptions. The two main exemption categories are:

Alternatives to methyl bromide

Because of the health and environmental concerns, several alternatives have been developed for treating wood pallets:

Cautions when handling MB-stamped pallets

• Do not use indoors: avoid MB-treated pallets for DIY projects, home decor or furniture.
• Do not burn MB pallets: burning can release toxic gases into the air and is dangerous.
• Assess the risk: companies should carry out a risk assessment and look to switch to safer treatment methods.

In short, while methyl bromide proved effective at treating wood pallets, its health and environmental impacts have made its use tightly restricted. Safer alternatives, led by heat treatment, are increasingly encouraged to protect public health and the environment.

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Frequently asked questions about methyl bromide

1. What is methyl bromide used for?

It is a broad-spectrum fumigant that kills fungi, insects, weeds, nematodes and rodents. It was widely used to treat soil, timber and farm produce, and to fumigate wood pallets under ISPM 15 before export.

2. Is methyl bromide banned?

Yes, in most major markets. The EU banned its use in 2005 and the US phased out most production and import. Today it is only allowed under narrow Critical Use and Quarantine and Preshipment (QPS) exemptions.

3. Why is methyl bromide harmful?

It is highly toxic to people, causing nervous system, respiratory and skin damage at high exposure, and it is a Class I ozone-depleting substance under the Montreal Protocol that thins the ozone layer.

4. What does the MB stamp on a pallet mean?

It certifies the wood pallet was fumigated with methyl bromide to meet ISPM 15. MB-stamped pallets should not be used indoors, made into furniture or burned.

5. What can replace methyl bromide?

Heat treatment (HT), where the wood core reaches at least 56C for at least 30 minutes, is the leading ISPM 15 alternative. Steam, biological treatment and Integrated Pest Management (IPM) are also used.

6. How long does MB fumigation take?

The treatment usually runs about 16 to 24 hours in a sealed chamber, after which the chamber is aerated to remove residual gas before the pallets are released.

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