AQIS has recently made changes to the minimum temperature requirements for the methyl bromide fumigation of timber and timber packaging. The changes mean AQIS will only accept methyl bromide fumigation treatments where the minimum temperature throughout the treatment period remains above 10°C. Previously, the minimum acceptable temperature had been 4°C.
However, there was a potential for this change to have disadvantaged industry, as it did not allow for a suitable introduction period to enable stakeholders to make the necessary changes to their systems. As a result, AQIS has delayed the introduction of the new minimum temperature for methyl bromide fumigation until 27 June 2004. Prior to this date, fumigations performed at temperatures down to 4°C will be accepted by AQIS.
Generally, packing timbers, timber and wooden articles must be fumigated with methyl bromide at a concentration of 48 g/m³ for 24 hours at a temperature of 21°C under normal atmospheric pressure (NAP). The maximum thickness of the timber should not exceed 200mm and it should be stacked in a manner which allows adequate gas circulation between pieces. Correct fumigation procedures must be used.
For each 5°C the temperature is expected to fall below 21°C, the fumigator must add 8 g/m³ of methyl bromide. For temperatures above 21°C, no dosage compensation is allowed by AQIS. Treatments undertaken below 10°C will not be accepted after 27 June 2004.
For example, the acceptable dosage rate at NAP after 27 June 2004 will be:
Methyl bromide under vacuum will be acceptable after 27 June 2004 if applied at:
Further information on AQIS requirements for methyl bromide fumigation is available in the AQIS publication Cargo Containers – Quarantine Aspects and Procedures, which can be accessed by clicking here. Alternatively, this document can be accessed from the AQIS website: www.aqis.gov.au.