The audit sheet · Check 04
Methyl bromide and fumigation: the gas, the risk area and imported goods
Methyl bromide is an odourless, colourless fumigant gas. The federal environment department says it can be used as a fumigant in Australia only for quarantine and pre-shipment purposes, treating goods being imported or exported so they are free of pests. Fumigating for any other purpose needs special approval, which the department says is granted only in limited circumstances. For goods bound for Australia, methyl bromide treatments done overseas come under the Australian Fumigation Accreditation Scheme, which trains and regularly assesses the providers registered with it.
General information, not safety advice. This page explains the hazards and the rules around fumigation; it is not a guide to fumigating. In Victoria, a licence holder may use only the pesticides their licence names, and fumigants have their own authorisation.
What the gas is
Methyl bromide controls a wide range of pests, including insects, spiders, mites, snails and rodents. It is toxic if breathed in or swallowed, and can irritate the eyes, the respiratory system and the skin. It is also highly volatile, so once vented it disperses quickly into the air.
It is recognised as ozone depleting. The Montreal Protocol, an international treaty, controls the manufacture and use of ozone-depleting substances, and the fact sheet says methyl bromide’s use has been retained for quarantine and pre-shipment purposes.
- 3 mThe minimum risk area around an outdoor fumigation enclosure under the AFAS standard and the Australian Standard, as Victoria’s 2018 fact sheet describes them.
- 24 hoursThe usual time the gas is held in the enclosure before it is vented or captured.
- 12Countries taking part in the Australian Fumigation Accreditation Scheme, as its page lists them.
How a fumigation runs, as the fact sheet describes it
- Stage 1
A plan for each job
The Australian Standard and the scheme’s methyl bromide standard both require a fumigation plan or risk assessment for every application of a fumigant.
- Stage 2
The enclosure is checked
Fumigation applies the gas inside an enclosed space, such as a shipping container. Purpose-built chambers are pressure tested regularly to show they are gas-tight; temporary enclosures are checked with sensitive instruments and significant leaks are fixed at the time, though the fact sheet notes every temporary enclosure leaks a little, and says the escaping gas disperses quickly and presents minimal risk.
- Stage 3
The gas is held
The gas must stay in the enclosure for the specified period.
- Stage 4
Vented or captured
Afterwards the gas is either vented at a controlled rate, so that concentrations outside the risk area stay below 5 ppm, or captured using activated carbon. In 2018 the fact sheet described 5 ppm as the Australian occupational exposure guideline, for exposure eight hours a day, five days a week; WorkSafe Victoria, which enforces Victoria’s occupational health and safety laws, is the place to ask about the workplace limit that applies now. The fact sheet calls recapture on activated charcoal filters a proven way of reducing exposures.
The risk area
A precautionary risk area must be set around a fumigation, and the standards require warning signs and a physical barrier at its edge.
The risk area exists so that people who are not wearing the required personal protective equipment are kept out of it. The fact sheet adds that the area is usually made larger during ventilation, depending on the weather.
The health risk is greatest for workers close to the fumigation area. They must wear a full face respirator or self-contained breathing apparatus when releasing the fumigant and while working in the risk area after it is released. Outside the risk area, the fact sheet says, there should be negligible risk to the general public.
Goods fumigated before they arrive
The Australian Fumigation Accreditation Scheme (AFAS) is an arrangement between the Australian Department of Agriculture, Fisheries and Forestry and participating overseas government agencies. It exists to manage the high biosecurity risk of ineffective methyl bromide treatments performed offshore. Treatment providers on its approved list have met the minimum registration and compliance requirements, and their treatments must comply with Australia’s import requirements and treatment methods. A provider suspended from another of the department’s assurance schemes is suspended from AFAS too.
The scheme’s page lists twelve participating countries: Cambodia, Fiji, India, Indonesia, Lao PDR, Malaysia, Papua New Guinea, Peru, the Philippines, Sri Lanka, Thailand and Vietnam. The department’s AFAS page links the list of approved treatment providers.
Who regulates it
The fact sheet says methyl bromide is strictly regulated in Australia, with controls at national and state level. It dates from June 2018 and names departments as they were then.
| Body | Its part |
|---|---|
| Commonwealth agriculture department | One of the authorities that can authorise a methyl bromide fumigation. Its Methyl bromide fumigation methodology, version 3.0, sets the minimum requirements for fumigating imports and exports for quarantine and pre-shipment, and treatment providers are audited against it. |
| Australian Pesticides and Veterinary Medicines Authority | Registers methyl bromide for use as a fumigant. |
| Commonwealth environment department | Administers the Ozone Act, which prohibits uses other than those the Montreal Protocol permits and licenses its manufacture, import and export. |
| Victoria’s health department | Licenses anyone using pesticides in a pest control business, including fumigating commodities for purposes other than agriculture and horticulture. |
| WorkSafe Victoria | Under the Occupational Health and Safety Regulations 2017, pest control operators must control the health risk of using hazardous substances. |
The standards the 2018 fact sheet named for Victoria were the AFAS Methyl Bromide Fumigation Standard and Australian Standard AS 2476-2008, General Fumigation Procedures. The agriculture department’s Methyl bromide fumigation methodology, version 3.0, now sets the minimum requirements for treatment providers fumigating with methyl bromide for quarantine and pre-shipment purposes. The licensing guide shows how to check a fumigant authorisation.
If someone may have been exposed
The Victorian Poisons Centre gives first aid information by phone and tells callers whether they need an ambulance; its number is on the Better Health Channel’s Poisons Centre page. In an emergency, call triple zero (000), not the Poisons Centre: that includes anyone who has collapsed, has stopped breathing, is having a seizure or has gone into anaphylactic shock.