The toxic gas
Methyl bromide, an ozone-depleting toxic gas harmful to humans, is banned in many countries, but New Zealand is using more than ever. Tony Wall asks why, and speaks to people who have faced pressure to keep quiet about it.
Every few minutes, a logging truck rumbles through the gates at the Port of Tauranga. More logs arrive by train. The wharves at Mt Maunganui are covered in huge stacks – there are so many logs they’ve had to store them in a yard nearby.
All this wood – 5.5 million tonnes of timber went through the port last year – has brought jobs and industry to the area. It’s also brought methyl bromide. Loads of it.
The gas is an extremely effective killer of all organisms and is used in small quantities to fumigate imported fruit, vegetables and other products. But by far the biggest users are timber exporters.
In 2016, 220 tonnes of the toxic, ozonedepleting gas was administered to logs at the Port of Tauranga to kill insects before export.
Another 250 tonnes was used at Northport near Whangarei, and 70 tonnes at Napier Port – making New Zealand the world’s fifth-biggest user of methyl bromide, and by far the biggest per capita.
Our consumption of the fumigant has rocketed from less than 100 tonnes in the early 2000s to about 600 tonnes today, mirroring a timber boom – log exports have tripled since 2008 and are now worth $2.7 billion.
Matthew Carratu couldn’t believe it when he took his young son Alex, who was recovering from cancer, sailing at the Tauranga Yacht Club at Sulphur Point and noticed container fumigations were happening just over the fence.
‘‘It was so close it was just ridiculous,’’ Carratu, an osteopath, says. ‘‘I come from the UK, where methyl bromide is banned. The fact that this ‘pure, green, 100 per cent place’ that we came to for a utopian experience does daft things like that is anathema.’’
Aubrey Wilkinson, a crane operator at the port and spokesman for the Tauranga Moana Fumigant Action Group, which aims to have methyl bromide eliminated or at least contained to a purpose-built facility, says the community has been slow to react.
‘‘I know down in Nelson there were huge campaigns and the community got behind it and battled the local council and the port.
‘‘I don’t think the community here was aware of what was happening over the fence, within the port. It makes me angry and something needs to be done about it.’’
Methyl bromide was used for decades as a soil fumigant for crops such as strawberries and potatoes but, under the Montreal Protocol aimed at protecting the ozone layer, it had to be phased out for all but quarantine purposes by 2005.
Countries are required to reduce its use and some, including those in the European Union, have banned it altogether. That’s not such a big deal for countries that export processed timber that doesn’t need treating.
But New Zealand mostly exports raw logs, and two of its biggest markets, India and China, insist they be treated with methyl bromide.
In 2010, the Environmental Protection Authority (EPA) mandated that methyl bromide be recaptured and destroyed for all fumigations in New Zealand by October 2020.
The timber industry and Genera, the company that does most of the log fumigations in New Zealand, have spent millions trying to develop recapture systems that can deal with the scale required for log stacks, with limited success.
It’s feared the 2020 deadline will be missed – already the industry is preparing an application to have the rules around methyl bromide reassessed.
‘‘I’ve just about got a clock on my wall heading to doomsday,’’ says Don Hammond, chairman of forestry industry group Stimbr (Stakeholders In Methyl Bromide Reduction).
But the fact is, he says, technology to fully recapture methyl bromide emissions from log stacks doesn’t exist.
‘‘We’re desperate to find a solution. We’re investing as much as we possibly can into finding a way out of this.’’
Methyl bromide is colourless and odourless, so people don’t know if they’ve been exposed. It’s heavier than air and can accumulate in poorly ventilated or low-lying areas.
According to the Ministry for Primary Industries, a single, small exposure is unlikely to cause long-term effects. But exposure to high concentrations can cause damage to the lungs and nervous system, or even death.
There’s a lack of research on the effects of long-term exposure to small amounts of the gas, but it’s been suspected in a number of cases of motor neuron disease in Nelson port workers, and associated with some cancers.
Methyl bromide can be recaptured and destroyed when used to fumigate containers, but with log stacks it’s pumped under tarpaulins and mostly vented to the atmosphere after about 24 hours.
Tauranga locals are concerned that, when the gas is vented, or if a tarpaulin rips in high winds, as occasionally happens, invisible plumes of gas could drift across the port and surrounding areas, affecting residents, workers, boaties, cruise ship visitors and a nearby marae.
Four port workers were taken to hospital in March after feeling dizzy and nauseous. Fumigation had been going on nearby but it’s still unclear if it was to blame; it’s understood blood tests didn’t show elevated methyl bromide levels.
A Bay of Plenty Regional Council investigator is continuing to review evidence, including video taken by a port worker showing the venting that was going on.
One of the stevedores who went to hospital claims it’s not the first time workers have been exposed – ‘‘it’s a common event’’ – and says some colleagues have refused to work when methyl bromide is being vented. ‘‘They just don’t come out of their huts if they’re de-tarping.’’
The worker says he wants to speak out but has been ‘‘muzzled’’.
‘‘If you don’t do what you’re told, you get removed off the board and they don’t give you work.’’
There have been no recorded instances of methyl bromide exceeding allowable levels at the port, but the fumigant action group says the plume could drift above monitoring equipment anyway.
Genera, which holds the consent to discharge methyl bromide, says independent studies have shown port workers are exposed to lower levels of methyl bromide than other toxicants at the port, and the gas is not as toxic as some other substances.
But the Environment Court has expressed concern. In a decision last year, dealing with an application by another company to use methyl bromide at the port, it said discharge limits have been exceeded on many occasions and noted there were problems with monitoring.
‘‘At this stage, we can express no confidence that the current use of methyl