FAQs: Phytosanitary fumigation for export logs and timber products
1. Methyl bromide
Q: What is methyl bromide?
A: Methyl bromide (CH3Br) is a colourless, odourless, non-flammable gas that is produced both industrially and by natural biological processes. Significant quantities – greater than produced for use in fumigations – are produced by natural sources, including the ocean, some plants, fungi and soil. Automobile emissions, burning of biomass and biofuel production also produce methyl bromide. Methyl bromide is manufactured for use at higher than the naturally occurring concentrations to kill unwanted pests associated with the movement of goods internationally.
Q: What are the characteristics of methyl bromide?
A: Methyl bromide is an odourless and colourless gas. It is liquid at temperatures below 3.5 degrees Celsius. It is three times heavier than air. Methyl bromide breaks down relatively quickly with a half-life of about seven months (A half-life of seven months means that half of the volume of the chemical will break down in that time period). Methyl bromide may pool in poorly ventilated and low lying areas. Approved fumigators carefully monitor conditions when applying methyl bromide to avoid this issue arising.
Q. If methyl bromide is a naturally occurring substance why is it an issue?
A: Methyl bromide was identified internationally as an ozone depleting substance and in 1989 was included in the United Nations’ Montreal Protocol on Substances that Deplete the Ozone Layer. Methyl bromide was one of a number of substances identified for phasing out in order to prevent further depletion of the ozone layer as decreased ozone allows increased ultra-violet (UV) radiation to reach the earth’s surface. The increased UV will potentially impact human health, the environment, and also agricultural crops.
Q: How much methyl bromide is manufactured and used in the world?
A: Total methyl bromide production in 2015 for Quarantine and Phytosanitary (QPS) usage was 8,450 tonnes of which 6,546 tonnes was used by 47 countries in 2015. Methyl bromide is manufactured in five countries for use internationally as a fumigant.
Q. How much methyl bromide is used in New Zealand?
A: Most methyl bromide used in New Zealand is for pre-shipment treatment of forestry products to meet importing countries’ quarantine requirements. Methyl bromide use for the 2016 calendar year was 602 tonnes. Historically as the volumes of treated products increase or decrease, so too does the amount of methyl bromide used.
Q: Does methyl bromide break down in the environment?
A: Yes it does. Methyl bromide is broken down by sunlight, chemical reactions in the air, water and by micro-organisms. Methyl bromide has a half-life of about seven months.
Q: Will methyl bromide contaminate groundwater?
A: No. Groundwater contamination is not likely to result from fumigations carried out under tarpaulins because methyl bromide most readily enters into air when vented following fumigation.
A: Methyl bromide (CH3Br) is a colourless, odourless, non-flammable gas that is produced both industrially and by natural biological processes. Significant quantities – greater than produced for use in fumigations – are produced by natural sources, including the ocean, some plants, fungi and soil. Automobile emissions, burning of biomass and biofuel production also produce methyl bromide. Methyl bromide is manufactured for use at higher than the naturally occurring concentrations to kill unwanted pests associated with the movement of goods internationally.
Q: What are the characteristics of methyl bromide?
A: Methyl bromide is an odourless and colourless gas. It is liquid at temperatures below 3.5 degrees Celsius. It is three times heavier than air. Methyl bromide breaks down relatively quickly with a half-life of about seven months (A half-life of seven months means that half of the volume of the chemical will break down in that time period). Methyl bromide may pool in poorly ventilated and low lying areas. Approved fumigators carefully monitor conditions when applying methyl bromide to avoid this issue arising.
Q. If methyl bromide is a naturally occurring substance why is it an issue?
A: Methyl bromide was identified internationally as an ozone depleting substance and in 1989 was included in the United Nations’ Montreal Protocol on Substances that Deplete the Ozone Layer. Methyl bromide was one of a number of substances identified for phasing out in order to prevent further depletion of the ozone layer as decreased ozone allows increased ultra-violet (UV) radiation to reach the earth’s surface. The increased UV will potentially impact human health, the environment, and also agricultural crops.
Q: How much methyl bromide is manufactured and used in the world?
A: Total methyl bromide production in 2015 for Quarantine and Phytosanitary (QPS) usage was 8,450 tonnes of which 6,546 tonnes was used by 47 countries in 2015. Methyl bromide is manufactured in five countries for use internationally as a fumigant.
Q. How much methyl bromide is used in New Zealand?
A: Most methyl bromide used in New Zealand is for pre-shipment treatment of forestry products to meet importing countries’ quarantine requirements. Methyl bromide use for the 2016 calendar year was 602 tonnes. Historically as the volumes of treated products increase or decrease, so too does the amount of methyl bromide used.
Q: Does methyl bromide break down in the environment?
A: Yes it does. Methyl bromide is broken down by sunlight, chemical reactions in the air, water and by micro-organisms. Methyl bromide has a half-life of about seven months.
Q: Will methyl bromide contaminate groundwater?
A: No. Groundwater contamination is not likely to result from fumigations carried out under tarpaulins because methyl bromide most readily enters into air when vented following fumigation.
2. Methyl bromide – International treaties, law and regulations
Q: Hasn’t methyl bromide use been banned by the United Nations?
A: Yes, it has been banned for all other purposes except for biosecurity and phytosanitary treatments. Methyl bromide is an ozone-depleting gas. There are international agreements limiting its use, particularly the United Nation’s Montreal Protocol. New Zealand is party to these agreements. Use of methyl bromide is permitted for phytosanitary purposes, including the export of logs and timber products. To prevent the movement of unwanted pests from one country to another. Just as New Zealand does not want new pests and diseases to get into our country, so too our trading partners do not want us to send them pest on products they buy from us. Methyl bromide is no longer available for use as a pre-plant fumigant for field crops. For example, before it was phased out one of the largest uses of methyl bromide was to sterilise soil prior to planting crops such as strawberries and potatoes.
Q. Which countries signed the Montreal Protocol?
A. New Zealand, together with 175 countries (including our significant trading partners), has signed the Montreal Protocol on substances that deplete the ozone layer.
Q. Why is methyl bromide being phased out of use?
A. The United Nations’ Montreal Protocol on Substances that Deplete the Ozone Layer (1989) and the Vienna Convention for the Protection of the Ozone Layer (1988) are committed to stopping depletion of the ozone layer. New Zealand is a signatory to both of these. Under the provisions of these agreements, signatory nations have since 2005 either banned or severely restricted the use of methyl bromide.
Q. What about the science linking methyl bromide to ozone depletion?
A. Methyl bromide is considered to be a significant ozone depleting substance by atmospheric scientists. The 2006 Scientific Assessment of Ozone Depletion https://esrl.noaa.gov/csd/assessments/ozone/2006/ contains a thorough discussion and analysis on the scientific understanding of ozone depletion.
Q: What is the Ozone Layer Protection Act?
A: The New Zealand Parliament passed the Ozone Layer Protection Act in 1996. The purpose of the Act is to phase out ozone-depleting substances, which includes CFCs and methyl bromide.
http://www.epa.govt.nz/hazardous-substances/ozone/Pages/default.aspx
Q. Why is New Zealand still using methyl bromide?
A. The use of methyl bromide for biosecurity and phytosanitary treatments is permitted by international agreements. These agreements however require countries to seek alternatives and to use those alternatives where possible.
Q: Is methyl bromide use in New Zealand permitted?
A: Methyl bromide importation and use in New Zealand is only permitted for biosecurity and phytosanitary purposes. These are currently the only permitted uses for methyl bromide in this country.
http://www.epa.govt.nz/hazardous-substances/ozone/Pages/default.aspx
Q: What are the international recommendations regarding methyl bromide?
A: The United Nations recommends a number of things that should be done:
Q: What is being done in New Zealand to comply with these recommendations?
A: The EPA determined in 2010, based on the available knowledge, that no methyl bromide emissions following the completion of fumigation would be allowed beyond 2020. Stakeholders in Methyl Bromide Reduction (STIMBR) invests in research seeking alternatives to methyl bromide, reduction in rates used, and technologies and tools to manage methyl bromide emissions as its stakeholders work toward the 2020 goal.
STIMBR raises its funds through a voluntary levy on the use of methyl bromide and phosphine. These funds are supplemented with co-funding from government, industry and trust funds where possible. To date about $13 million has been invested in research.
A: Yes, it has been banned for all other purposes except for biosecurity and phytosanitary treatments. Methyl bromide is an ozone-depleting gas. There are international agreements limiting its use, particularly the United Nation’s Montreal Protocol. New Zealand is party to these agreements. Use of methyl bromide is permitted for phytosanitary purposes, including the export of logs and timber products. To prevent the movement of unwanted pests from one country to another. Just as New Zealand does not want new pests and diseases to get into our country, so too our trading partners do not want us to send them pest on products they buy from us. Methyl bromide is no longer available for use as a pre-plant fumigant for field crops. For example, before it was phased out one of the largest uses of methyl bromide was to sterilise soil prior to planting crops such as strawberries and potatoes.
Q. Which countries signed the Montreal Protocol?
A. New Zealand, together with 175 countries (including our significant trading partners), has signed the Montreal Protocol on substances that deplete the ozone layer.
Q. Why is methyl bromide being phased out of use?
A. The United Nations’ Montreal Protocol on Substances that Deplete the Ozone Layer (1989) and the Vienna Convention for the Protection of the Ozone Layer (1988) are committed to stopping depletion of the ozone layer. New Zealand is a signatory to both of these. Under the provisions of these agreements, signatory nations have since 2005 either banned or severely restricted the use of methyl bromide.
Q. What about the science linking methyl bromide to ozone depletion?
A. Methyl bromide is considered to be a significant ozone depleting substance by atmospheric scientists. The 2006 Scientific Assessment of Ozone Depletion https://esrl.noaa.gov/csd/assessments/ozone/2006/ contains a thorough discussion and analysis on the scientific understanding of ozone depletion.
Q: What is the Ozone Layer Protection Act?
A: The New Zealand Parliament passed the Ozone Layer Protection Act in 1996. The purpose of the Act is to phase out ozone-depleting substances, which includes CFCs and methyl bromide.
http://www.epa.govt.nz/hazardous-substances/ozone/Pages/default.aspx
Q. Why is New Zealand still using methyl bromide?
A. The use of methyl bromide for biosecurity and phytosanitary treatments is permitted by international agreements. These agreements however require countries to seek alternatives and to use those alternatives where possible.
Q: Is methyl bromide use in New Zealand permitted?
A: Methyl bromide importation and use in New Zealand is only permitted for biosecurity and phytosanitary purposes. These are currently the only permitted uses for methyl bromide in this country.
http://www.epa.govt.nz/hazardous-substances/ozone/Pages/default.aspx
Q: What are the international recommendations regarding methyl bromide?
A: The United Nations recommends a number of things that should be done:
- Replacement of methyl bromide use as a phytosanitary measure where possible
- Reducing rates of methyl bromide where it is used as a phytosanitary measure
- Reducing methyl bromide emissions
- Recording methyl bromide use as a phytosanitary measure
- Guidelines for the appropriate use of methyl bromide as a phytosanitary measure should be followed
Q: What is being done in New Zealand to comply with these recommendations?
A: The EPA determined in 2010, based on the available knowledge, that no methyl bromide emissions following the completion of fumigation would be allowed beyond 2020. Stakeholders in Methyl Bromide Reduction (STIMBR) invests in research seeking alternatives to methyl bromide, reduction in rates used, and technologies and tools to manage methyl bromide emissions as its stakeholders work toward the 2020 goal.
STIMBR raises its funds through a voluntary levy on the use of methyl bromide and phosphine. These funds are supplemented with co-funding from government, industry and trust funds where possible. To date about $13 million has been invested in research.
3. Methyl bromide – Use as a fumigant
Q: What is a phytosanitary treatment?
A: Phytosanitary treatments are prescribed by importing countries to reduce the likelihood of unwanted pests arriving in their country and establishing. New Zealand prescribes phytosanitary treatments for all plant materials and products imported into New Zealand to protect our environment, people, taonga and economy. Other countries have the right to do the same for products they import, such as those from our forest and horticulture products.
Q. Why is methyl bromide used as a fumigant?
A. Methyl bromide gas is highly toxic when used at high concentrations during fumigation. Methyl bromide is used as a phytosanitary treatment because it penetrates the commodity being treated (logs) killing unwanted pest species that are under bark or inside the log.
Q. Does methyl bromide have adverse effects on produce?
A. Methyl bromide has adverse effects on some produce, including loss of viability in seeds that are not properly ventilated following fumigation. It can have a significant effect on quality and shorten the shelf life of some fresh produce. However, those considerations are not important when treating logs, wood and other inert products.
Q. How long do log fumigations take?
A. Specific treatment times are determined by the importing country. Methyl bromide fumigations are completed within 24 hours.
Q: What is done to protect users when methyl bromide is used as a fumigant?
A: Methyl bromide use is controlled by the Environmental Protection Authority (EPA). In 2010, expert toxicologists and risk assessors at the EPA have analysed the risk associated with methyl bromide and developed controls using a rigorous scientific approach. The controls determined by the EPA must be followed when methyl bromide is used. Councils at their discretion are able (under the Resource Management Act 1991) to determine additional rules which must also be complied with. Fumigators are required to follow all of these rules.
Q. What measures are taken to ensure safety during methyl bromide fumigations?
A. Fumigations are monitored and include defined buffer areas to ensure that any methyl bromide released is able to disperse to safe levels long before it goes beyond the buffer areas’ boundaries. The current advice from monitoring agencies is that such measures are sufficient to protect human and environmental health.
Q: What risk management measures are in place?
A: Stringent measures are in place to ensure that methyl bromide and phosphine use does not affect human and environmental health. Licensed treatment applicators must work within guidelines set by the Environmental Protection Authority (EPA) and regional or unitary councils. Monitoring of air for methyl bromide presence occurs at all treatment sites where methyl bromide is used.
Stakeholders in Methyl Bromide Reduction (STIMBR – www.stimbr.org.nz) has been advised by the EPA that the EPA “considers existing controls for methyl bromide are fit-for-purpose and applicable.”
Q: What assurances do we have of this?
In a Reassessment of Methyl Bromide in 2010 the EPA determined a set of controls that it deemed appropriate to mitigate identified risks.
Methyl Bromide Reassessment Decision 2010 and related documents can be found here:
http://www.epa.govt.nz/search-databases/Pages/site-results.aspx?k=methyl%20bromide%20reassessment%20decision%202010
The EPA confirmed in February 2017 that the controls determined for methyl bromide in 2010 “are fit-for-purpose and applicable.”
A: Phytosanitary treatments are prescribed by importing countries to reduce the likelihood of unwanted pests arriving in their country and establishing. New Zealand prescribes phytosanitary treatments for all plant materials and products imported into New Zealand to protect our environment, people, taonga and economy. Other countries have the right to do the same for products they import, such as those from our forest and horticulture products.
Q. Why is methyl bromide used as a fumigant?
A. Methyl bromide gas is highly toxic when used at high concentrations during fumigation. Methyl bromide is used as a phytosanitary treatment because it penetrates the commodity being treated (logs) killing unwanted pest species that are under bark or inside the log.
Q. Does methyl bromide have adverse effects on produce?
A. Methyl bromide has adverse effects on some produce, including loss of viability in seeds that are not properly ventilated following fumigation. It can have a significant effect on quality and shorten the shelf life of some fresh produce. However, those considerations are not important when treating logs, wood and other inert products.
Q. How long do log fumigations take?
A. Specific treatment times are determined by the importing country. Methyl bromide fumigations are completed within 24 hours.
Q: What is done to protect users when methyl bromide is used as a fumigant?
A: Methyl bromide use is controlled by the Environmental Protection Authority (EPA). In 2010, expert toxicologists and risk assessors at the EPA have analysed the risk associated with methyl bromide and developed controls using a rigorous scientific approach. The controls determined by the EPA must be followed when methyl bromide is used. Councils at their discretion are able (under the Resource Management Act 1991) to determine additional rules which must also be complied with. Fumigators are required to follow all of these rules.
Q. What measures are taken to ensure safety during methyl bromide fumigations?
A. Fumigations are monitored and include defined buffer areas to ensure that any methyl bromide released is able to disperse to safe levels long before it goes beyond the buffer areas’ boundaries. The current advice from monitoring agencies is that such measures are sufficient to protect human and environmental health.
Q: What risk management measures are in place?
A: Stringent measures are in place to ensure that methyl bromide and phosphine use does not affect human and environmental health. Licensed treatment applicators must work within guidelines set by the Environmental Protection Authority (EPA) and regional or unitary councils. Monitoring of air for methyl bromide presence occurs at all treatment sites where methyl bromide is used.
Stakeholders in Methyl Bromide Reduction (STIMBR – www.stimbr.org.nz) has been advised by the EPA that the EPA “considers existing controls for methyl bromide are fit-for-purpose and applicable.”
Q: What assurances do we have of this?
In a Reassessment of Methyl Bromide in 2010 the EPA determined a set of controls that it deemed appropriate to mitigate identified risks.
Methyl Bromide Reassessment Decision 2010 and related documents can be found here:
http://www.epa.govt.nz/search-databases/Pages/site-results.aspx?k=methyl%20bromide%20reassessment%20decision%202010
The EPA confirmed in February 2017 that the controls determined for methyl bromide in 2010 “are fit-for-purpose and applicable.”
4. Methyl bromide – Use in New Zealand
Q: How many logs are exported from New Zealand?
A: The Ministry for Primary Industries advises that New Zealand provisionally exported 15.4 million cubic metres of logs in the year to December 2016. The majority of these logs (10.5 million cubic metres) were exported to China and 1.6 million cubic metres to India.
The volumes for forestry exports to all countries are available at the following links. Click the link to download the file:
A: Countries that import logs and timber products from New Zealand do not want to import our forest insect pests. They have strict standards – referred to as importing country phytosanitary requirements – regarding the methods used to exterminate such pests from products destined for their markets. The Ministry for Primary Industries must present strong scientific evidence to support the use of a given phytosanitary treatment before approval is given by importing countries.
Q: How is methyl bromide used as a fumigant?
A: Methyl bromide is applied in carefully measured quantities. Treatment of logs and timber products happens in a confined space such as under a tarpaulin or in a ship’s hold to ensure that it does its job exterminating unwanted pests. When methyl bromide is used for fumigating logs in New Zealand it disperses quickly on release at the end of fumigation.
Q: How much methyl bromide is used in New Zealand?
A: Methyl bromide use has declined from 571 tonnes in 2013 to 522 tonnes in the year to December 2015. This reduction is related to a reduction in the number of export logs requiring phytosanitary fumigation over the same period. As log exports increase, so too does the usage of methyl bromide.
The United Nations reports annual global production and consumption.
http://ozone.unep.org/en/data-reporting/data-centre
Q: What portion of exported logs is treated with methyl bromide?
A: About 28% of exported logs are treated with methyl bromide onshore in New Zealand. About 65% are fumigated with phosphine whilst in transit to China. The balance are debarked as a risk reduction measure which is only permitted by China.
Q: Hasn’t methyl bromide been linked to motor neurone disease and other adverse human health conditions?
A: No it has not. The Ministry of Health determined in 2005 that there is no evidence to indicate that exposure to methyl bromide within the prescribed mitigations is connected with motor neurone disease or any other health condition.
Three documents prepared by the Ministry of Health are available at this reference: http://www.stimbr.org.nz/our-resources.html
A: The Ministry for Primary Industries advises that New Zealand provisionally exported 15.4 million cubic metres of logs in the year to December 2016. The majority of these logs (10.5 million cubic metres) were exported to China and 1.6 million cubic metres to India.
The volumes for forestry exports to all countries are available at the following links. Click the link to download the file:
- Year ended 30 June 1996 to most recent [XLS, 313 KB]
- Year ended 31 December 1996 to most recent [XLS, 326 KB]
A: Countries that import logs and timber products from New Zealand do not want to import our forest insect pests. They have strict standards – referred to as importing country phytosanitary requirements – regarding the methods used to exterminate such pests from products destined for their markets. The Ministry for Primary Industries must present strong scientific evidence to support the use of a given phytosanitary treatment before approval is given by importing countries.
Q: How is methyl bromide used as a fumigant?
A: Methyl bromide is applied in carefully measured quantities. Treatment of logs and timber products happens in a confined space such as under a tarpaulin or in a ship’s hold to ensure that it does its job exterminating unwanted pests. When methyl bromide is used for fumigating logs in New Zealand it disperses quickly on release at the end of fumigation.
Q: How much methyl bromide is used in New Zealand?
A: Methyl bromide use has declined from 571 tonnes in 2013 to 522 tonnes in the year to December 2015. This reduction is related to a reduction in the number of export logs requiring phytosanitary fumigation over the same period. As log exports increase, so too does the usage of methyl bromide.
The United Nations reports annual global production and consumption.
http://ozone.unep.org/en/data-reporting/data-centre
Q: What portion of exported logs is treated with methyl bromide?
A: About 28% of exported logs are treated with methyl bromide onshore in New Zealand. About 65% are fumigated with phosphine whilst in transit to China. The balance are debarked as a risk reduction measure which is only permitted by China.
Q: Hasn’t methyl bromide been linked to motor neurone disease and other adverse human health conditions?
A: No it has not. The Ministry of Health determined in 2005 that there is no evidence to indicate that exposure to methyl bromide within the prescribed mitigations is connected with motor neurone disease or any other health condition.
Three documents prepared by the Ministry of Health are available at this reference: http://www.stimbr.org.nz/our-resources.html
5. Methyl bromide – Seeking alternatives
Q: Is any work being done to find alternative phytosanitary treatments or ways of using methyl bromide more safely?
A: The Stakeholders in Methyl Bromide Reduction (STIMBR) is leading New Zealand’s efforts to identify sustainable alternative biosecurity treatments for export log and timber products within a significant research programme.
STIMBR has identified some potential alternative treatment measures. It has also identified ways to possibly capture and destroy methyl bromide following fumigation. Research continues to find ways to cost-effectively deliver these treatments.
Q: Why is methyl bromide not being recaptured when log stacks are fumigated?
A: Despite claims to the contrary, no effective and sustainable recapture/destruction technologies are available for use on commercial scale log stacks and ship holds. Methyl bromide being used in small-scale fumigations can however be effectively destroyed on completion of the fumigation. A number of New Zealand businesses have projects underway to develop suitable systems for log fumigation. None have been commercially finalised to date.
Q. Why are we not using alternative phytosanitary treatments to methyl bromide?
A. New Zealand commenced using phosphine as an alternative to treat export logs bound for China in 2001. China also permits the use of debarking as a risk reduction strategy. STIMBR has an extensive research programme that is seeking suitable alternative treatments to methyl bromide and technologies and tools to manage methyl bromide emissions.
STIMBR also supports the Ministry for Primary Industries when it is negotiating with trading partners about what their phytosanitary requirements are. Just as New Zealand is able to impose whatever requirements it wishes on products entering this country to protect ourselves from the arrival of a new pest or disease, so too our trading partners can impose their requirements on us when we wish to export to them. As a result, it can be a slow process to get changed treatment schedules or fumigations accepted by trading partners.
Q: What about phosphine, which is also used as a fumigation treatment for export logs?
A: Phosphine (PH3, also known as phosphane, hydrogen phosphide or phosphorous hydride) is used as an in-transit fumigant treating logs in the holds of ships while they are at sea. The International Maritime Organisation permits phosphine use and has rules that must be complied with. Logs that are stowed on deck cannot be treated with phosphine. The same International laws prevent the use of methyl bromide on ships while at sea.
Q. What is phosphine and why is it being used?
A. Phosphine is widely used as a grain fumigant. It is also an industrial gas used in silicon chip manufacture, an air pollutant and a natural product of swamps and sewers.
Phosphine is a cost-effective treatment. Its major disadvantage is its slow action, (3 to 10 days for fumigation) consequently it is used as an in-hold (while the ship travels to market) log treatment or silo treatment for grains. China allows New Zealand to use phosphine as a phytosanitary treatment for logs. No other trading New Zealand partner accepts phosphine as a phytosanitary treatment.
Q: Why does New Zealand use methyl bromide and phosphine for fumigation, both of which are highly toxic?
A: Without these treatments the New Zealand export log trade would stop. Methyl bromide and phosphine fumigation are currently the only approved fumigants available as phytosanitary treatments for New Zealand’s major export markets (China and India). China allows either treatment along with debarking as a risk reduction process. India will only allow the use of methyl bromide.
Q: Why is phosphine used while ships are at sea?
A: Phosphine has a different mode of action to methyl bromide when used against the target insects as it requires 10 days to be effective, whereas methyl bromide is dose dependant and a fumigation using methyl bromide can be completed in as little as 16 hours for logs being exported to China.
Q: Shouldn’t biosecurity fumigation be undertaken at remote sites, rather than at ports, most of which are close to areas of intensive human habitation?
A: MPI requires that logs must be loaded onto ships within 36 hours of fumigation. If the ship does not depart within 36 hours, the fumigation must be redone. The related logistics dictate that methyl bromide treatments must occur close to the ship onto which they will be loaded.
A: The Stakeholders in Methyl Bromide Reduction (STIMBR) is leading New Zealand’s efforts to identify sustainable alternative biosecurity treatments for export log and timber products within a significant research programme.
STIMBR has identified some potential alternative treatment measures. It has also identified ways to possibly capture and destroy methyl bromide following fumigation. Research continues to find ways to cost-effectively deliver these treatments.
Q: Why is methyl bromide not being recaptured when log stacks are fumigated?
A: Despite claims to the contrary, no effective and sustainable recapture/destruction technologies are available for use on commercial scale log stacks and ship holds. Methyl bromide being used in small-scale fumigations can however be effectively destroyed on completion of the fumigation. A number of New Zealand businesses have projects underway to develop suitable systems for log fumigation. None have been commercially finalised to date.
Q. Why are we not using alternative phytosanitary treatments to methyl bromide?
A. New Zealand commenced using phosphine as an alternative to treat export logs bound for China in 2001. China also permits the use of debarking as a risk reduction strategy. STIMBR has an extensive research programme that is seeking suitable alternative treatments to methyl bromide and technologies and tools to manage methyl bromide emissions.
STIMBR also supports the Ministry for Primary Industries when it is negotiating with trading partners about what their phytosanitary requirements are. Just as New Zealand is able to impose whatever requirements it wishes on products entering this country to protect ourselves from the arrival of a new pest or disease, so too our trading partners can impose their requirements on us when we wish to export to them. As a result, it can be a slow process to get changed treatment schedules or fumigations accepted by trading partners.
Q: What about phosphine, which is also used as a fumigation treatment for export logs?
A: Phosphine (PH3, also known as phosphane, hydrogen phosphide or phosphorous hydride) is used as an in-transit fumigant treating logs in the holds of ships while they are at sea. The International Maritime Organisation permits phosphine use and has rules that must be complied with. Logs that are stowed on deck cannot be treated with phosphine. The same International laws prevent the use of methyl bromide on ships while at sea.
Q. What is phosphine and why is it being used?
A. Phosphine is widely used as a grain fumigant. It is also an industrial gas used in silicon chip manufacture, an air pollutant and a natural product of swamps and sewers.
Phosphine is a cost-effective treatment. Its major disadvantage is its slow action, (3 to 10 days for fumigation) consequently it is used as an in-hold (while the ship travels to market) log treatment or silo treatment for grains. China allows New Zealand to use phosphine as a phytosanitary treatment for logs. No other trading New Zealand partner accepts phosphine as a phytosanitary treatment.
Q: Why does New Zealand use methyl bromide and phosphine for fumigation, both of which are highly toxic?
A: Without these treatments the New Zealand export log trade would stop. Methyl bromide and phosphine fumigation are currently the only approved fumigants available as phytosanitary treatments for New Zealand’s major export markets (China and India). China allows either treatment along with debarking as a risk reduction process. India will only allow the use of methyl bromide.
Q: Why is phosphine used while ships are at sea?
A: Phosphine has a different mode of action to methyl bromide when used against the target insects as it requires 10 days to be effective, whereas methyl bromide is dose dependant and a fumigation using methyl bromide can be completed in as little as 16 hours for logs being exported to China.
Q: Shouldn’t biosecurity fumigation be undertaken at remote sites, rather than at ports, most of which are close to areas of intensive human habitation?
A: MPI requires that logs must be loaded onto ships within 36 hours of fumigation. If the ship does not depart within 36 hours, the fumigation must be redone. The related logistics dictate that methyl bromide treatments must occur close to the ship onto which they will be loaded.