The weedkiller is used to control annual grasses and broadleaf weeds in vegetable growing globally. File picture. Photo: Unsplash / Arnaldo Aldana
The Environmental Protection Authority admits it does not know the extent to which a weed killer linked to birth defects is used in New Zealand.
Chlorthal Dimethyl, also known as Dacthal or DCPA, is used for some vegetable crops, forest nurseries and ornamental plants.
It is now been banned in the US.
The New Zealand EPA has issued a red alert which recommends people stop using products that contain the chemical and to consider alternatives.
"If people can't avoid using these products, the EPA advises they take all precautions to avoid exposure for people who are pregnant or could be pregnant," the statement said.
"This includes restricting access to sprayed areas and making sure nobody else is around during spraying," it said.
Authorities warn growers not to use herbicide linked to birth defects
EPA spokesperson Dr Shaun Presow told Checkpoint they had had the information for less than two weeks and were putting together a working group to look at it more closely.
"We're reviewing the US EPA's actions and we're talking with industry to see how big of a problem it actually could be here."
Any decisions on Dacthal would then be reviewed and that could include banning it or restricting its use, he said.
Under New Zealand's Hazardous Substances and New Organisms Act it was impossible to ban a substance outright without following certain steps, he said.
Suspending a product was allowable under the HSNO Act but only after specific application was in place which took time, he said.
The Environmental Protection Authority only had a part of the information from the US EPA which was why they were requesting further information from industry, he said.
Presow said people who did need to use the chemical should try and do so as safely as possible.
"We'd encourage people to take as many pragmatic measures as they can including signage, restricting entry to areas, anything that they think is appropriate to maximise the safety."
There were currently no import records to indicate how much of the chemical was imported nor where it was being used, he said.
"We've just passed the new amendment to our importers and manufacturers notice that will allow us to collect that information in the future and improve our information in the EPA."
If Dacthal was used on a field where vegetables were growing you should stay out of that field for 25 days or more, he said.
Farmers have been encouraged to not use the substance and to use an alternative, he said.
The substance had been in use globally since the 1950s and the latest US EPA information showed no indication that there was any danger to people who were not pregnant, he said.