New Zealand Introduces New Requirements for Clopyralid Products to Prevent Compost Contamination

On 12 March 2026, new regulatory requirements for products containing clopyralid enter into force in New Zealand. The measures introduced by the Environmental Protection Authority (EPA) aim to reduce the risk of compost contamination caused by residues of the herbicide.

Updated Labelling and Supply Requirements

From 12 March 2026, clopyralid products must carry specific label statements warning about the risks of compost contamination and restrictions on the disposal of treated plant material.

Suppliers may continue selling products with existing labels during a transitional period until 12 March 2027. However, all products placed on the market after that date must fully comply with the updated labelling requirements.

The new rules also specify that clopyralid products may only be sold to workplaces, ensuring that they are used by trained or professional users.

Restrictions on Disposal of Treated Vegetation

The updated requirements emphasise that grass clippings, plant material, or manure from animals that have grazed on clopyralid-treated vegetation must not be composted or used in mulch or fertilisers. Such materials should instead be disposed of through appropriate waste management routes, such as landfill, to avoid contaminating compost products.

Background: Clopyralid Residues in Compost

Clopyralid (CAS No. 1702-17-6) is a selective herbicide commonly used to control broadleaf weeds in grassland, turf, and certain crops. However, the substance can remain active in treated plant material and pass through composting processes without breaking down.

If contaminated plant waste enters composting systems, the herbicide residues may persist in finished compost and damage sensitive plants when the compost is later used in gardens or horticulture.

EPA has introduced the updated requirements to reduce the likelihood of clopyralid entering compost streams and to ensure that users are aware of appropriate disposal practices.