The Port of Tauranga says it is "too soon to say" what impact the approval of a new alternative gas for fumigating logs could have.
This week the Environmental Protection Authority approved an application for gas EDN to fumigate export logs and timber in New Zealand.
It's a tool tokill common pests found in wood and is a potential alternative to methyl bromide, which is used at the Port of Tauranga.
Fumigation removes harmful micro-organisms by completely filling an area with gaseous pesticides - or fumigants - to suffocate or poison the pests within. Methyl bromide is used but is a colourless, odourless, toxic, non-flammable gas. Trading nations such as India and China require it to be used on New Zealand logs.
In the Bay of Plenty, methyl bromide is used primarily for quarantine or pre-shipment applications and the fumigator needs resource consent.
Dr Chris Hill, general manager of the authority's hazardous substances group, said the new gas has "reduced risks to human health and the environment compared with methyl bromide".
"The benefits of EDN are that it rapidly decomposes after use, it is ozone-friendly."
Logs stacked at the Port of Tauranga. Photo / NZME
Czech-based manufacturer Draslovka applied for approval to import the gas into New Zealand.
Even though the application has been approved, the authority said the fumigant could not be imported or used immediately as WorkSafe rules to protect workers now require ministerial sign-off and gazetting.
Hill said once additional WorkSafe rules and the authority's approval were in place, it would be up to industry and port operators to determine whether the fumigant was suitable for their sites.
The use of methyl bromide at Tauranga's port has been an issue for several years.
In 2017 the Environment Court blocked an application by Envirofume Ltd to fumigate logs for export using methyl bromide at the port.
That year methyl bromide user Genera Biosecurity pledged to filter methyl bromide at the port and phase out a method in which most of the gas was released into the air.
Mount Maunganui residents railed against the continued use of the fumigant as part of an industry request to reassess controls for use of the ozone-depleting substance.
Tarpaulins and methyl bromide gas being used at Port of Tauranga to treat logs in 2017. Photo / NZME
However it was understood EDN was "potentially" an alternative to methyl bromide, she said.
Port of Tauranga continued to support "de-barking" as an alternative to using methyl bromide and it insisted on "recapture of 100 per cent of methyl bromide fumigations to minimise environmental impacts".
She said if log exporters or fumigators wished to use EDN at the port they would need to apply for resource consent from the Bay of Plenty Regional Council.
The countries receiving the exports would also need to approve EDN's use as a phytosanitary treatment for products from New Zealand, she said.
Australia, South Korea, Malaysia and Russia have already approved use of the gas.
Bay of Plenty Regional Council compliance manager Stephen Mellor said resource consent would set conditions on how it could be used, any associated risk mitigation required and associated monitoring and reporting requirements.
"(The regional council) will be closely monitoring future EDN fumigations to ensure that the established exposure limits and any other resource consent conditions are complied with."
Genera was approached for comment.
In late 2020 its then chief executive Mark Dewdney said the company understood methyl bromide was a "difficult issue".
At that time he said it was not possible to replace methyl bromide use in all applications or markets "as alternatives either do not exist, are not registered for use in New Zealand, or are not accepted by New Zealand's trading partners".
The authority's decision means the Ministry for Primary Industries can progress negotiations with trading partners on acceptance of EDN, as an option to meet their import biosecurity requirements.
