Woman 'seriously ill' after caravan treated with methyl bromide

Tuesday, 26 February 2019

The Ministry for Primary Industries has launched an investigation after an Auckland woman fell violently ill when her imported caravan was treated with methyl bromide to kill some ants.

Trish Honey, who lives in Oratia, said she suffered symptoms about 30 minutes after entering the caravan and it took weeks to fully recover.

She is scathing of New Zealand's use of methyl bromide - a toxic, ozone-depleting gas which has to be phased out under international protocols. And she is furious that MPI told her the treatment was safe.

MPI has apologised for failing to respond when Honey emailed via its website in December.

After inquiries by Stuff, the ministry said it had asked its auditors to investigate the treatment provided by biosecurity company Genera, which handles most of the country's methyl bromide fumigations.

'We are investigating the treatment provided by Genera to see if they did not follow our biosecurity treatment schedule,' a spokesman said.

Genera's chief executive, Mark Self, said he didn't know about the incident, which occurred in early December, until contacted by Stuff so did not have all the details.

He doubted that Honey's illness was caused by methyl bromide because the caravan would have been fully vented before leaving the Ports of Auckland.

But he admitted the substance could react with rubber products such as door seals and bed mattresses, and it could continue to release gases, called mercaptans, for a long time.

'I think the most likely explanation for this incident is that [Honey] is reacting to the very strong, unpleasant and nauseating smell of mercaptan.'

Honey rubbishes that theory, as mercaptans - the same odour that comes from pulp and paper mills - are not considered harmful.

MPI said it's thought people need to be exposed to one part per million of ethyl mercaptan to experience 'discomfort and irritation' but the effects are not disabling and disappear quickly.

The caravan arrived at Honey's property on December 3 after being treated - she uses the term 'nuked' - a couple of days earlier.

She had bought the caravan from her brother in Australia and had it brought over, cleaning it thoroughly before it was shipped.

Honey, 61, grows her own food and hates chemicals, but had signed a waiver allowing the van to be treated after assurances the process was safe.

A skull and crossbones sticker on the caravan said to vent it for one hour and 20 minutes before entering.

To make sure, Honey called MPI.

'They said 'it's safe, you don't need to clean it, it's had all the methyl bromide taken out of it before it leaves the wharf',' Honey said.

She vented the caravan overnight and about lunchtime the next day went inside to clean it, which was when she noticed a chemical smell.

'It was about 30 minutes before I started to feel real crook. The last thing I did was wipe the floor over … that was possibly the worst thing I could have done because this gas is heavier than air, so it sinks.'

She lay down, and was mostly bedridden for the next two weeks.

'At first I thought it was the 'flu, but it was so quick. Usually when you get the 'flu you build up the symptoms, but these just hit me, 'bang'.'

She said she was dizzy, nauseous, feverish, had a pounding headache and sore eyes, was severely fatigued and disoriented and had bizarre dreams.

Scientific papers say some of those symptoms are common after acute exposure to methyl bromide.

Honey didn't see a doctor for 10 days - 'I don't like doctors much, either' - and by the time she had a blood test the levels of bromide in her body were normal, which experts say can happen as soon as two days after exposure.

Ian Shaw, Professor of Toxicology at Canterbury University, said most of Honey's symptoms were neurological so could have been caused by methyl bromide exposure, although it's not possible to tell from the symptoms alone.

There can be considerable variability in toxic response between individuals, he said.

Methyl bromide is used to fumigate everything from export logs to imported fruit and vegetables and New Zealand is one of the world's biggest users.

There have been reports of port workers around the country suffering symptoms similar to Honey's after fumigations of log stacks.

Honey said it took six weeks for her to fully recover, and she has lost about 6kg in weight.

The MPI spokesman said officers inspected the caravan on November 28 and found six ants as well as 'external contamination', so issued a treatment direction notice.

Options were heat treatment or fumigation with methyl bromide - it was up to the importer and treatment provider to decide which.

Self, of Genera, said they preferred to use heat treatment rather than methyl bromide but caravans contained plastic fittings that could be damaged by that method.

'Fumigation was clearly chosen to minimise the risk of damage,' he said.

He was unsure what was done to protect items inside the caravan such as mattresses and foam rubber - included on the list of items on the Genera disclaimer form which shouldn't be exposed to methyl bromide.

'As the treatment was for ants it would not be appropriate to exclude any part of the caravan from treatment.' 

Genera used photo-ionisation devices to monitor levels of gas and did not finish ventilation until levels were below safe thresholds, Self said.

While it couldn't be ruled out, he said, it was 'very unlikely' that enough gas remained to cause the symptoms described by Honey.

'The reason that fumigants are used for biosecurity work is that they are very mobile, they penetrate quickly to hard to reach areas and they are released quickly also.'

Self said the amount of time an item such as a caravan should be vented after delivery to its owner was 'not technically calculated' but an hour would be a 'reasonable precaution'.

It was not necessary to provide people with information about possible side effects, he said, 'as the methyl bromide is vented such that health effects are not of concern'.

But Self said there were 'plenty of cases' where rubber and rubber products such as tyres, car seats, door seals and mattresses had reacted with methyl bromide, releasing mercaptans.

'They smell nauseatingly terrible, even at low concentrations,' Self said.

'The reaction triggered by the methyl bromide continues long after venting, I am aware of an imported vehicle that was…smelling unpleasant for years after treatment, venting, washing and heat treatment were all tried.'

Asked if Genera should stop using methyl bromide on goods containing rubber, Self said there were limited options and the company applied treatments as instructed by MPI.

'Sending infested consignments back to port of origin remains as the lowest risk option for New Zealand.'

The MPI spokesman said methyl bromide had been used for over 70 years as a quarantine treatment and was safe if correct procedures were followed.

MPI was looking to reduce the use of the gas and was seeking alternatives.

'Most of our treatment options do include an alternative but it can be more expensive or take longer and it is the importer's choice which to use.'

But Honey said she had no say in what type of treatment was used - that was discussed between her shipping agent and Genera.

'We were not asked, just told 'sign this waiver', which included both heat treatment or methyl bromide. I had no clue, I'd never heard of it.'

She is concerned that methyl bromide has a half-life in the environment of several months.

'I just want my bloody van cleaned - at the moment we still can't even walk inside it. It's absolutely ridiculous - what the hell is New Zealand doing?

'It's an ozone depleting gas, we have the highest skin cancer rate in the world and they're using methyl bromide that makes the situation worse - not to mention putting it inside a caravan.'