EPA signals reassessment of allowing herbicide US and Australia have banned

Greenpeace says it is unbelieveable New Zealand is continuing to use a herbicide which is now banned in both Australia and the United States.

In August the United States took an unprecedented move in banning Dacthal or DCPA herbicides, used for weed control in vegetable growing, citing possible irreversible damage to unborn children.

It was the first time in 40 years the US EPA has done an emergency stop on the chemcials because of the potential harm they can do to foetal development.

Now Australia is following the United States, completely banning the use of products containing chlorthal dimethyl.

Following the US ban, New Zealand's Environmental Protection Authority reviewed dacthal use and introduced stricter rules around application.

On Tuesday its hazardous substances reassessments manager told RNZ it has begun a reassessment of the herbicide, which is a legal requirement before a ban can be considered.

Greenpeace executive director Russel Norman said the EPA should stop its use immediately.

"It is outrageous that the New Zealand EPA is allowing these chemicals to be used. When you look at the conditions they're apparently imposing on the use of these chemicals you're somehow supposed to know whether you may or may not be pregnant if you're a farm worker, and then you've got to somehow avoid going onto a farm which in the previous five days has maybe used these chemicals.

"I just think it's completely irresponsible to put farm workers in that position where they have to make those decisions around a chemical which everyone else is banning," he said.

Norman said he would write to the EPA to get dacthal use here banned but doubted he would be successful.

Chlorthal dimethyl is not widely used in New Zealand and Norman said because of that, a ban would have little effect and should be easy to do.

He said in the United States DCPA is widely used and banning its use would have signficicant impacts for vegetable growers, but the US EPA still went ahead with the ban.

The Environmental Protection Authority said it may follow the United States and Australia in banning the use of DCPA herbicides in New Zealand - but it could be a year before that ban comes into effect.

Reassessment on ban possible - EPA

EPA hazardous substances reassessments manager Shaun Presow said new rules were imposed on the herbicide's use following the US ban.

The EPA believed the rules protected people's health and it was in the process of reassessing the chemical's use.

The process could not be rushed through because of legal requirements.

"There are hoops we need to go through. These take time. We need to have an application for reassessment submitted before we could potentially suspend the approvals," he said.

A ban was possible, but in the meantime the EPA believed the rules it imposed in September safeguarded people's health.

DCPA weedkillers can only be used on onions, garlic, and shallots before they emerge from the ground, and only once per calendar year.

Users must maintain wide buffer zones to further protect the public.

Presow said these crops weren't sprayed directly, and the substance broke down before harvest, so "we can assure people there is no risk through exposure from vegetables".

In New Zealand, there are two products containing the herbicide that are approved by MPI for use -Dacthal and Chlor-Back 75 WG.

Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.