Data released by transport agency Waka Kotahi reveals the controversial weed-killer glyphosate, which was once described as “probably carcinogenic” by the World Health Organization, is sprayed on most of the major highways in New Zealand.
The numbers, released to 1News under the Official Information Act, show highway contractors sprayed about 30,000 litres of the chemical each year in 2019, 2020 and 2021 in a massive programme of work.
Their spraying stretches the length of the country, covering all regions managed by the agency, with Northland, Auckland, Bay of Plenty, Waikato, Canterbury and Otago tallying some of the biggest amounts.
Do you have information about glyphosate use in New Zealand? Email Thomas.Mead@tvnz.co.nz
While the chemical is unlikely to cause harm to passing motorists, it has been embroiled in controversy for years as scientists, regulators and lawyers debate whether it can cause cancer.
The World Health Organization’s International Agency for Research on Cancer (IARC) classified glyphosate as a “probably carcinogenic to humans” in 2015, but many environmental regulators disagree, including those here in New Zealand.
Campaigners believe the spraying is an example of excessive use of glyphosate in this country, and are calling for a ban on roadside spraying.
Jodie Bruning, of the Soil and Health Organisation, argues we would be better served by the robot technology currently emerging in Europe.
“New Zealand is drenched with glyphosate, and the herbicides that are sprayed alongside it to deal with herbicide resistance,” she told 1News.
“I think we have to move away from the neat, tidy, ‘Simpsons’ image of a really super clean landscape, because that actually isn't healthy for anyone.”
The herbicide is very widely used the world over, included in popular products like Roundup, and dozens of countries and states have since moved to ban or restrict its use.
Controversy came to a head in 2018 when American school groundskeeper Dewayne Johnson sued Roundup manufacturer Monsanto, after developing an aggressive cancer named non-Hodgkin's lymphoma.
He won his case in a US court and was awarded a massive pay-out and a huge class action lawsuit with 95,000 plaintiffs soon following. They went on to reach a $10 billion settlement with Monsanto’s new owner Bayer. The company continues to deny the allegations.
New Zealand’s Environmental Protection Agency (EPA) disagrees with the World Health Organization, and says glyphosate is safe to use as long as the correct procedures are followed.
However, they are currently running a “call for information” about the chemical, asking the public to write in as the regulator has no idea how much of the herbicide is used here.
Some are now calling for glyphosate to be formally reviewed in New Zealand including University of Canterbury Professor Ian Shaw.
The toxicologist says glyphosate is very widely used and while it’s unlikely to have a short-term impact in places like motorways, the long-term exposure is less certain.
“People who might be driving past when glyphosate is being sprayed, their risk is minimal because their exposure will be very small,” he said.
“If you're a contractor and you're spraying every day then that's a significant risk and you need to be protected against it.”
Waka Kotahi refused to be interviewed about the safety of their contractors, despite repeated requests, but said in a statement they are confident the highway works follow "the appropriate health and safety measures".
Their general manager of safety, health and environment, Greg Lazzaro, wrote that they undertake “routine audits”.
“Glyphosate is one of the most widely-used treatments for weed-control globally, approved for commercial and personal use in New Zealand and used extensively here and overseas,” he said.
“The use of this weed-killer is carried out under certain restrictions to ensure the health and safety of our contractors and the wider public.”
However, some like Professor Shaw, believe roadside spraying is an area that could be reassessed if the EPA chose to do a review.
“We know a lot about the short-term, and that's a minimum, that's not a problem, but the long-term we know an awful lot less about,” he said.
“What we could think about doing perhaps, but it needs the review to do this, is to say, 'well, let's think about how glyphosate is used. What do we really need it for? Do we need to spray the side of the road? Do we need it in agriculture?’”
That review is still possible depending on what happens with the EPA’s “call for information”, which has recently been extended to conclude on Friday October 22.
The public are welcomed to contact the EPA to share information about how they use glyphosate.