NZ's problem with toxic methyl bromide has a possible solution

Thursday, 31 May 2018

Logs are fumigated at the Port of Tauranga - there is debate about the best way to deal with residual methyl bromide.

Methyl bromide, an ozone depleting toxic gas harmful to humans, is banned in many countries but New Zealand is using more than ever. In the final part of a three-part investigation, Tony Wall reveals how a potential solution remains untested because of bickering.

Mark Self holds a device he calls his Geiger counter while behind him at the Port of Tauranga a strange looking machine on the back of a tractor sucks methyl bromide from under a tarpaulin.

The chief executive of Tauranga-based fumigation company Genera is keen to show the effectiveness of the company's prototype gas liquid scrubber, which rains a solution down on the toxic gas and breaks it down to its component parts.

The monitoring device, which picks up everything from a puff of exhaust from a passing truck to elevated levels of methyl bromide, is showing miniscule traces of volatile compounds - well below permitted workplace levels.

If the device started 'squeaking', Self says, workers would simply increase the buffer zone and move back.

* Methyl bromide killed my husband**

Mark Self of fumigation company Genera is skeptical that an Australian company has the answer to our methyl bromide problem.

'You could paint me as an environmental vandal - the biggest user of methyl bromide in New Zealand - but I'm proud of the fact we've reduced emissions and built a world-first [recapture machine],' says Self, who regards himself as an environmentalist.

The trouble is, just around the corner workers wearing gas masks are 'venting' methyl bromide from another stack of logs - removing the tarpaulin and letting the gas into the atmosphere.

A monitoring device shows 0.6 parts per million of all organic gases. The workplace exposure standard for methyl bromide over eight hours is five parts per million.

There's only one scrubbing machine - and far too many logs. So at the moment, only about 25 per cent of Genera's log stack fumigations are subject to recapture.

That means a lot of gas is being vented - up to 50 per cent remains after a fumigation. In 2016, Genera used 220 tonnes of the stuff in Tauranga alone. It does all the country's log fumigations on behalf of exporters.

Genera and the timber industry are in a race against time to either find a system capable of dealing with log stack emissions or an alternative fumigant acceptable to trading partners.

Activated carbon granules used for capturing methyl bromide.

The Bay of Plenty Regional Council has given Genera until April 2019 to be using recapture technology for all fumigations in Tauranga.

The Environmental Protection Authority's (EPA) deadline for total recapture nationwide is October 2020 - in order to meet our international obligations to protect the ozone layer.

An Australian company that specialises in fumigation solutions believes it has the answer to New Zealand's methyl bromide problem, but says the timber industry is stalling because it doesn't want to spend the money - an accusation the industry strongly denies.

Nordiko Quarantine Systems produces a recapture system where the gas is ventilated through filters filled with activated carbon granules - basically charcoal from burnt coconut husks.

The methyl bromide sticks to the carbon, which is then disposed of in landfills. Genera currently uses the technology for container fumigations in Nelson.

Joe Falco, Nordiko's technical manager, says the company is ready to upscale to log stacks and has offered to fund a trial at Tauranga or Northport. (Australia is also a big user of methyl bromide, but doesn't fumigate logs in the open).

The equipment is in New Zealand ready to go, Falco says, but the project has stalled because timber exporters have insisted on a non-disclosure agreement preventing Nordiko from sharing results of the trial.

Logs at Tauranga's port, with Mount Maunganui in the background.

'We didn't see the value of holding a trial that we would pay for and not be allowed to share the results to the regulators or anybody else.'

Falco claims the industry is putting profit before environmental and health concerns.

'At a meeting we had last year there was concern by the industry that if the trials proved successful, that a mandate for recapture would occur…and that would increase the cost to export the logs.'

Don Hammond, chairman of the forestry industry group STMBR (Stakeholders in Methyl Bromide Reduction) says that's not true.

'It's not about us not wanting to mandate a system - we're desperate to find a system that works.'

He says the proposed non-disclosure agreement is standard, 'to ensure that disclosures are not selective, telling only one side of the story'.

Hammond says exporters had asked Nordiko to provide a project plan with clearly defined scope and outcomes and that hadn't happened.

He says the biggest stumbling block with the Nordiko system is what to do with the contaminated carbon.

A methyl bromide fumigation is carried out at the Port of Tauranga.

'They bury it in landfill, which is wrong. I'm sorry but I don't believe that is a solution.

'What we're saying to all these commercial operators like Nordiko is, you invest some of your capital, do some trials, show us the data and if we think this has got legs then we'll spend our money to validate it and support it.'

Falco says the contaminated carbon is disposed of safely by Chemwaste following EPA regulations.

Trials are about to begin on removing methyl bromide from the carbon so it can be used again, he says.

The Bay of Plenty Regional Council is a supporter of the Nordiko plan.

'We feel that Nordiko, on the face of it, offers potential so it really needs to be trialled on a full scale,' says Sam Weiss, the council's senior regulatory officer.

'We think it's important that trial goes ahead - unless you have the trial, how do you really know? We are trying to facilitate something there to make it happen.'

Hammond says whatever the solution, it needs to be practical and affordable.

Already the methyl bromide bill is in the millions, he says, and it's expected to double once full recapture is required, making some log exports uneconomic.

Record log volumes are being exported from New Zealand, lifting our methyl bromide consumption.

'We're talking about needing to fumigate millions of tonnes of logs a year.'

Self says the Nordiko option is not a long-term solution. 'They're burying a plastic pod full of methyl bromide and saying 'let the grandchildren sort that out'.'

He's travelled the world looking for effective recapture systems that can deal with the scale required for log stacks.

There basically aren't any, he says, but he recently convinced his board to buy a $500,000, experimental system from China which hopefully will allow the gas to be captured and re-used.

'We've thrown every bit of resource we can at it,' he says. 'We've got a long way to go but a few years ago it was impossible to do any recapture [from logs].

'I'm not looking at doing anything other than achieving [the recapture target] - I'm not looking at failing.'

Self used to be a regulator with the Ministry of Agriculture and Forestry and organised a delegation to China in 2001, convincing the Chinese to accept logs fumigated with phosphine.

'That saved 80 per cent of our methyl bromide emissions but we don't get credit for that.'

Phosphine is also toxic but does not damage the ozone layer. It takes a lot longer to work and so is only suitable for logs stored in ship's holds, allowing the gas to be vented while at sea.

For logs transported above deck - about 20 per cent of the total - methyl bromide remains the only option, and India doesn't accept phosphine.

Government officials have been in talks for years with China over phytosanitary options for logs. China is the world's biggest user of methyl bromide but plans to ban it from next year, according to reports.

Pete Thomson, a spokesman for the Ministry for Primary Industries, says MPI officials were part of a delegation to China last year to discuss alternatives, and Chinese officials visited New Zealand research facilities in October to view progress on other treatments.

'Similar talks have commenced with India and more are planned,' he says.

Self believes the risk of methyl bromide has been over-stated. Sure it needs to be recaptured to protect the ozone layer, he says, but it's not as toxic to humans as some other fumigants and remains the best 'tool in the biosecurity toolbox'.

'You can't see it, hear it, taste it, touch it and yet it can kill you - of course that's scary. So what do you do? You have to trust the likes of the EPA and work with a whole lot of processes that keep it safe.'