DCPA herbicides: New Zealand investigating weedkiller banned in US

Dacthal or DCPA herbicides are used to control annual grasses and broadleaf weeds in vegetable growing globally.

By Monique Steele of RNZ

The Environmental Protection Authority is investigating how a weedkiller that was banned in the United States last week is used in New Zealand.

Dacthal or DCPA herbicides are used to control annual grasses and broadleaf weeds in vegetable growing globally.

They contain the chemical compound dimethyl tetrachloroterephthalate or chlorthal-dimethyl.

But last week, the US Environmental Protection Agency announced the immediate suspension of all registrations for the herbicide, citing possible irreversible damage it could cause to unborn children.

Michal Freedhoff of its office of chemical safety and pollution prevention said pregnant mothers exposed to DCPA could experience changes to fetal thyroid hormone levels - which were linked to low birth weight, impaired brain development, decreased IQ, and impaired motor skills later in life.

“DCPA is so dangerous that it needs to be removed from the market immediately,” Freedhoff said.

“It’s EPA’s job to protect people from exposure to dangerous chemicals.

“In this case, pregnant women who may never even know they were exposed could give birth to babies that experience irreversible lifelong health problems.

“That’s why for the first time in almost 40 years, EPA is using its emergency suspension authority to stop the use of a pesticide.”

It has triggered a swift response from New Zealand regulators.

The authority said it was following the actions being taken in the US about the potential effects of the chemical, an approved hazardous substance with controls in New Zealand.

“We take very seriously any significant new information about the potential effects of chemicals that are currently used in New Zealand,” a spokesperson said.

“Products containing dimethyl tetrachloroterephthalate are used mostly in commercial settings and there are rules in place around how to safely use the substance.”

Hazard assessments highlighted possible organ damage through prolonged or repeated exposure to chlorthal-dimethyl - as well as it being toxic to aquatic life.

“We have now set up a working group to review the current uses for dimethyl tetrachloroterephthalate in New Zealand and decide what actions we need to take.”

WorkSafe was in contact with the authority following the developments abroad too, a spokesperson said - adding that there were workplace requirements for training and personal protective equipment around its use.

Vegetables New Zealand said it did not collect data on agrichemical use by its members - and Onions New Zealand has been approached for comment.

A mid-sized Pukekohe-based company selling agri-chemicals said it did not sell the product and has not stocked it since 2013.

A large celery grower told RNZ he did not know of it being used in that crop.

Horticulture New Zealand declined to comment.

- RNZ