Fumigation of logs next to the Ōpāwaho Heathcote River appears to continue the exploitative relationship of industry with the river.  Should we raise a fumigation alert about methyl bromide in the river environment?

In the Portlink Industrial Park, nestled beside the Ōpāwaho Heathcote River, a new enterprise has started up.  International Primary Products NZ Ltd (IPPNZ) is purchasing pinus radiata logs (mostly) from within 150km of Christchurch, trucking them onto its site beside the river, loading them into containers, fumigating the logs with methyl bromide and shipping them to China and India.  

It is a tidy operation and it is all being rather closely supervised by the Ministry for Primary Industries (MPI) and the Environmental Protection Agency (EPA) due to methyl bromide being something of a nasty chemical. Methyl bromide scavenges oxygen which makes it suitable for killing bugs; depleting the oxygen within a confined space with methyl bromide for long enough will kill any living organisms within that space. 

IPPNZ staff take the following steps when fumigating

• The containers are placed on a concrete pad and examined for leaks; any openings are taped closed
• Containers are then packed with logs
• Monitoring lines and a gas line are threaded into the containers
• The contents of the containers are warmed to increase efficiency and methyl bromide gas is introduced, with checks made for leaks
• The containers are then covered with a tarpaulin, although this is not so much for retention of gas as it is for reducing the effect of wind on the containers while also helping to maintain the temperature control
• Testing is done around the containers and a cordon set up where gas is detected above 50ppm concentration. This can be up to 10m from the containers. Containers under treatment are kept 25m from the site boundary
• The fumigation process usually takes 16 hours – it is typically done in the afternoon and left overnight
• Venting of the fumigated containers takes account of wind direction, with measurements of detected methyl bromide made at downwind boundaries. All staff wear appropriate breathing apparatus and access to the site is controlled while fumigation is being performed. 

Due to it being an ozone-depleting chemical, from 1 January 2023, all methyl bromide gas remaining in the containers after fumigation is required to be pumped out and captured on activated carbon that will then itself be buried in a dangerous goods dump.

While fumigation with methyl bromide is not ideal given its ozone destruction ability and toxicity at high concentrations, IPPNZ appears to be a well-run and frequently monitored operation. It’s likely that it does not present any substantive risk to the environment along and in the river or to recreational users in the area. This will be especially true once the recapture process is underway next year and there will be very little release of gas into the environment. There is a small risk of an accidental release from storage or handling, but this seems to be well-managed.

The one mis-step in the setting up of this operation was that it was able to commence operations without Environment Canterbury (ECan) being aware of it through a Resource Consent application for a discharge to air. This appears to have been an inter-agency communication issue between MPI, EPA and ECan, something that ECan is seeking to rectify given that this important process is meant to ensure that affected local residents are informed and are able to reassured about the safety measures involved.

We would like to thank IPPNZ owner Phil Juene who welcomed to us on the site and was generous with his time while being forthcoming, knowledgeable and obviously willing to comply with the fumigation rules.