A public health professor is calling for national restrictions on Roundup weed killer.
- Monsanto slammed with $439m verdict in Roundup cancer trial
- Monsanto’s pesticide 'unlikely to cause cancer'
- RoundUp probably doesn't cause cancer - study
Monsanto, the makers of the herbicide, were ordered to pay hundreds of thousands of dollars to Dewayne Johnson, a groundskeeper who developed cancer.
Monsanto intends to appeal the decision, but in the meantime, what does it mean for Kiwis using the same product?
Massey University Centre for Public Health Research professor John Potter told The AM Show glyphosate - a key ingredient in Roundup - has officially been designated a "probable carcinogen" by the cancer research arm of the World Health Organisation.
German company Bayer, who owns agriculture giant Monsanto, says herbicides containing glyphosate are safe.
"There are a large number of countries who have banned or restricted the use of it," Mr Potter said.
And yet, in New Zealand there are no restrictions on the product.
"A lot of people assume that because it's so widely available and so widely used, that there are no problems with it," Mr Potter said.
"We need to begin to think seriously about whether it should be banned for domestic use, which is probably a good step."
He also said councils who use the weed killer on verges, greens and schools should reconsider their use, as should wider agriculture businesses who use it.
"Those council and agriculture workers are the most exposed because they're using it regularly. Often the effects of these things are cumulative."
After three days of deliberations, a San Francisco jury awarded Dewayne Johnson US$250 million (NZ$380 million) in punitive damages and around US$39 million (NZ$59 million) in compensatory damages.
Now, his victory could pave the way for thousands of other cases alleging the glyphosate-based herbicide causes non-Hodgkin's lymphoma.
Mr Potter says Roundup is the most widely used herbicide in the world.
"I don't know what the rules are about disposing of it but we'd have to ask EPA [Environmental Protection Agency]. It'd be a good idea to see it off the shelves at the supermarkets and Mitre 10 and so on."
Mr Potter said if plants become resistant to Roundup, the next strongest weed killer is 2,4-D. 2,4-D is an ingredient used in Agent Orange, a herbicide widely weaponised during the Vietnam War.