Source: Environmental Protection Authority
The Environmental Protection Authority (EPA) has significantly restricted the use of chlorthal-dimethyl (also known as DCPA) because of concerns about its effects on fetal development.
The new rules come after the EPA’s red alert on 22 August 2024 urging people to stop using weedkillers that contain this chemical.
The alert closely followed the United States Environmental Protection Agency banning the substance earlier in August.
United States data found the substance can affect fetal development and cause low birth weight and irreversible, life-long impacts, such as impaired brain development and motor skills.
The EPA has introduced restrictions to New Zealand so the weedkiller can only be used on soil where specific crops are grown, pregnant individuals or individuals who may be pregnant are prevented from using the substance or entering a site where it’s been used, and wide buffer zones further protect the public from spray.
All restrictions on the use of products containing chlorthal-dimethyl took effect from 13 September 2024.
“Putting these restrictions in place now is the quickest and most effective way for us to protect people’s health and safety,” says Dr Shaun Presow, Hazardous Substances Reassessments Manager.
“We have consulted with organisations that use this herbicide, and we have found that it’s not widely used in New Zealand, especially compared with the United States.
In New Zealand, chlorthal-dimethyl is used mainly for controlling a specific weed in onion, garlic, and shallot crops before the vegetables emerge from the soil.
“These crops aren’t sprayed directly, and the substance breaks down before harvest, so we can assure people there is no risk through exposure from vegetables,” says Dr Presow.
The EPA’s next steps are to gather and analyse all information on how these weedkillers are used in New Zealand, before carrying out a full review that may lead to further restrictions or a ban.
- The US EPA found a risk of hormone changes in the unborn children of pregnant bystanders, and women who apply chlorthal-dimethyl, or those who enter treated fields after the substance has been applied.
- Chlorthal-dimethyl, also referred to as dimethyl tetrachloroterephthalate, DCPA, or chlorthal-methyl, is used commercially to control grasses and other weeds.
- The New Zealand restrictions on chlorthal-dimethyl have been made under section 64A of the Hazardous Substances and New Organisms Act (HSNO Act). This allows a hazardous substance to be restricted in specified circumstances, places, or for classes of persons for one year while reassessing the substance.
- The three products containing chlorthal-dimethyl that are registered for use in New Zealand are:
o Deramot Xtra
o Chlor-Back 75WG
- The EPA consulted with organisations identified as using chlorthal-dimethyl products from 20-30 August 2024, and received seven responses from manufacturers, importers, suppliers, and users.
