Data Loading...

Methyl Bromide (MBr) (((MBr)aboratories Flipbook PDF

Page 1 of 3 Methyl Bromide (MBr) (((MBr)aboratories Methyl bromide (MBr) is a chemical historically used as a fumigant b

171 Views
96 Downloads
FLIP PDF 242.64KB

Page 1 of 3

Methyl Bromide (MBr) (((MBr)aboratories Methyl bromide (MBr) is a chemical historically used as a fumigant both in agriculture and quarantine. Since January, 2005, its use has been prohibited in Australia other than for quarantine use. Fumigation is required to prevent unwanted pests from being imported into Australia from other countries.

MBR is considered an ozone depleting substance and its use in Australia is being restricted more and more to comply with the Montreal Protocol. The Australian Quarantine and Inspection Service (AQIS) Regulations and procedures require certain imported commodities in containers to be fumigated with MBr. MBr penetrates without leaving traces of its intrusion into a product. For this reason produce such as edible fruits and vegetables are regularly treated with MBr for the extermination of pests. Cargoes such as timber, which can house a variety of unwanted visitors such as borers, are also most effectively treated by MBr fumigation because the gas is able to penetrate up to approximately 17 centimetres of timber from all sides. The vast majority of this chemical is manufactured by three companies: two in the U.S. and one in Israel. These companies utilise naturally occurring bromide salts, which are either contained in underground brine deposits (as is the case with Arkansas), or in highly concentrated above ground sources like the Dead Sea. MBr is also produced as a by-product of other bromide manufacturing processes. MBr is an odourless, colourless, toxic gas. Exposure to this chemical will affect not only the target pests, but also non-target organisms as well. Because MBr dissipates so rapidly to the atmosphere, it is most dangerous at the fumigation site itself. Human exposure to high concentrations of MBr can result in central nervous system and respiratory system failure, as well as specific and severe effects on the lungs, eyes, and skin. Fumigation related exposures have resulted in throat and eye irritation, skin injuries, shortness of breath, pain in chest, nausea, fatigue, dizziness, numbness, and weakness of extremities. Central nervous symptoms can emerge, including numbness, respiratory, gastrointestinal, and neurological problems, inflammation of nerves and organs, degeneration of eyes, muscle spasms, lack of balance, extreme agitation, coma and convulsions. Exposure to high concentrations has resulted in a number of human deaths. To make the fumigant gas more readily detectable, MBr is commonly mixed with small amounts of chloropicrin. Chloropicrin is also a fumigant which gives off a strong, sharp, highly irritating odour and is also sometimes used as a tear gas. Chloropicrin is also dangerous and poisonous if inhaled in high concentrations. Repeated minor exposure to chloropicrin can have a cumulative poisoning effect.

© 3M 2012. All rights reserved.

Page 2 of 3

Methyl Bromide Employees should be tested to establish bromide levels and regular blood tests are recommended for employees at intervals not exceeding 12 months.

Why there is a health and safety risk from fumigated containers? People unloading MBr fumigated containers have become ill from exposure to residual fumes. This was because there has been little or no flushing of the container with fresh air prior to an entry. Although regulations require fumigated containers to be ventilated and fumigant levels to be tested immediately after the fumigation process, it’s known that the levels of compliance may vary. Effective ventilation of a fumigated container over 24 hours will disperse MBr residues in the majority of cases. The doors of container should be fully open and facing a breeze. Use of a fan will also assist ventilation. Even if ventilation and testing for fumigant levels are carried out properly, it’s still possible for dangerous levels of MBr to occur inside the container. This can happen is if ambient temperature rises after the container has been tested—if there are particularly fibrous or absorbent products inside, these can off-gas and potentially dangerous levels of MBr can build-up inside the container. People involved in the handling of the contents of a fumigated container should be trained in how to unload a container safely. Various OH&S Regulations cover specific actions manufacturers, suppliers and employers must do to protect people’s health at work from hazardous substances MBr and chloropicrin are clearly defined as hazardous substances.

Respiratory Protection All respiratory protection in Australia should follow the guidelines of Australian Standards AS/NZS1715 and AS/NZS1716 in regards to respirators, their selection and application. AS/NZS1715 contains general information on the processes and programs required to achieve appropriate respiratory protection in the workplace. AS/NZS1716 sets the performance requirements for various types of respirators. There are a number of issues to be considered in regards to respiratory protection for MBr: 

There is a standard defined class of gas filter for MBr. These filters are tested specifically against MBr and meet the requirements of AS/NZS1716 and should be used rather than AX filters.



Use of any gas/vapour filter, particularly against a colourless, odourless gas like MBr, requires a clear knowledge of exposures to determine an appropriate filter change schedule. The health of the wearer depends on the filter working as it should - knowing the life of the filter is critical so it is changed at appropriate intervals.

© 3M 2012. All rights reserved.

Page 3 of 3

Methyl Bromide 

Wearers using any gas filter (MBr or other type) need to be very clear on its performance- they should seek specific information from the supplier/manufacturer as to whether it meets the Australian Standard and its service life performance against MBr at expected concentrations.



Anecdotal evidence suggests that AX filters are commonly being used for MBr protection. This is potentially hazardous and clear information on the performance of these filters against MBr should be sought from the supplier/manufacturer. Their performance against MBr may not meet the performance requirements of S/NZS1716 for an MBr filter and this presents a clear risk to the wearer. Again, the filter change time information is critical and some filters will not be suitable for use with MBr.



The actual exposures associated with fumigation work in containers is variable. The MBr levels in each container will vary depending on factors like contents, empty space, exposure time, airing time, temperature etc. Under extremely variable conditions like this it is very difficult to be sure filters are not being overexposed and no longer protecting the wearer.

NOTE: All of the above issues also apply to chloropicrin if this is used in the same mixture with MBr.  without the need for chemical filters. Clean air coming from a source (e.g. air compressor) outside the container and supplied to a suitable headtop will protect the wearer from high levels of MBr and chloropicrin indefinitely and will not be affected by varying levels of fumigant in each container. 3M does not recommend the use of Filtering systems for respiratory protection from MBr in containers. We strongly recommend that Airline systems are used unless an AS/NZS1716 compliant MBr Filter is used in conjunction with a respiratory protection program meeting the requirements of AS/NZS1715 and ALL other relevant exposure information is known and taken into consideration by an Occupational Hygienist or other Health Professional. ____________________________________

Occupational Health and Environmental Safety Division 3M Australia Pty Limited Building A, 1 Rivett Road North Ryde NSW 2113 Phone: 136 136 TechAssist Helpline: 1800 024 464 Email: [email protected] Website: www.3m.com/au/ohs © 3M 2012. All rights reserved.

Occupational Health and Environmental Safety Division 3M New Zealand Ltd PO Box 33246 Takapuna, North Shore City 0740 Tech Helpline: 0800 364 357 Email: [email protected] Website: www.3m.co.nz/safety