The popular weed killer Roundup tops the lists of successful ACC claims for injuries related to herbicides, pesticides and insecticides.

ACC accepted 359 claims for injuries involving Roundup since 1990 and a further 20 where its active ingredient glyphosate was named.

Since 2000, ACC declined 60 claims for injuries involving Roundup and 14 involving glyphosate.

The corporation had paid out $875,000 for injuries related to Roundup since 1990 and $6241 for glyphosate over the same period.

By comparison, the products with the next highest number of successful claims are 2,4,5-T and 2,4-D for which ACC has accepted just 15 claims, while rejecting a further 30.

These related products were made at Ivon Watkins Dow's Paritūtū plant in New Plymouth from 1960 to 1987.

Prior to this Ivon Watkins produced herbicides including 2,4,5-T, at its Buller St plant in the central city from 1948.

They contained toxic dioxins linked to cancers and birth defects and were a key component of Agent Orange - the defoliant used by the US military during the Vietnam War.

ACC paid out about $380,000 for injuries related to 2,4,5-T and 2,4-D including 12 gradual process injuries - a work-related illness or injury that developed over time.

Roundup was not identified in any gradual process injury claims received by ACC.

Injuries involving herbicides, pesticides and insecticides included burns, cuts, foreign body in orifice/eye and inhalation/ingestion among others.

ACC accepted the most claims for burns, scalding or corrosive injuries - 335 - and the least for inhalation/ingestion - 82.

The inhalation/ingestion claims were the most expensive with the corporation paying out $370,551, while foreign body in orifice/eye cost it the least - $13,404.

The insurance provider accepted 949 claims where the claimant only identified the offending product as a herbicide, pesticide or insecticide in broad terms.

Those claims had cost ACC just shy of $1.2 million since 2000.

Twelve of those claims involved gradual process injuries.

Some research has linked Roundup - one of the world's most popular weedkillers - and its active ingredient glyphosate, to cancer and its use has been restricted in some countries.

In New Zealand the Environmental Protection Authority was responsible for regulations for Roundup and glyphosate.

General Manager Hazardous Substances and New Organisms, Dr Chris Hill, said specific carcinogenicity studies had not confirmed a link between cancer and glyphosate.

He said the EPA continually monitored international developments and reviewed global research on hazardous substances, including glyphosate.

"Glyphosate has not been banned by any major regulatory jurisdiction. A ban would be where an active ingredient is completely withdrawn from the market within a country.

"Individual countries may place specific restrictions or controls around an active ingredient's use, similar to the rules we have put in place around the required personal protective equipment for glyphosate."

Hill said after extensive review, the European Union in December 2023 approved the use of glyphosate for a further 10 years, and the Federal Court of Australia in December 2024 dismissed all litigation claiming glyphosate caused cancer.

"In New Zealand, we have no evidence that risks associated with using glyphosate, or its hazardous nature, have changed to warrant a reassessment and potential restriction of uses, and we maintain that the risks of using glyphosate can be managed through following the rules of use."

Those rules included people wearing personal protective equipment (PPE) such as gloves, goggles and boots; applying sprays during calm and dry conditions, at designated usage rates and storing the product appropriately.

Hill said in 2024, the EPA received a request for grounds to reassess glyphosate and glyphosate-containing formulations on the basis of significant new information.

"The EPA found that the information provided, as well as other existing information, was not significant enough to warrant grounds being granted, and declined the request. A judicial review of this decision has been requested, and will take place in 2025."

The EPA was always looking for ways to ensure people and the environment were protected, Hill said, and would continue to review any new research on glyphosate that showed a change in the risks and was relevant to the New Zealand context.

German multinational company Bayer makes Roundup after acquiring the brand from Monsanto.

In a statement, the company said it stood behind its glyphosate-based products, which had been used safely and successfully around the world for 50 years.

"Roundup and glyphosate-based herbicides have been rigourously tested in hundreds of studies, with the weight of this extensive body of science confirming that glyphosate is safe when used as directed and is not carcinogenic."

The company said health regulators in Germany, Australia, New Zealand, Korea, Canada, Japan and elsewhere around the world had repeatedly concluded that glyphosate-based products could be used safely as directed and that glyphosate was not carcinogenic.

Director of the Hugh Adam Cancer Epidemiology Unit at University of Otago, Associate Professor Brian Cox, said the International Agency for Research Against Cancer (IARC) classified glyphosate (the major herbicidal component of round-up) as a probable carcinogen.

"That classification is not unusual for many compounds they assess and is indicative of quite a bit of uncertainty in the results of the scientific studies of the effects of Roundup on human health."

Cox said the EPA in the US considered Roundup to be safe if used as directed.

"From my assessment of whether there is a relationship between Roundup use and cancer, I am inclined to agree with the EPA."

It was very difficult to get an accurate measure of long-term (at least five years) exposure to Roundup, Cox said, and whether the product had been inhaled or absorbed via the skin which greatly altered the body's uptake of the compound.

"Mis-measurement of exposure is known to considerably influence the measures used to assess the health risk from any compound and this can create spurious associations between disease and exposure."

Cox said this was one of the reasons the IARC had not identified Roundup as a definite carcinogen.

-RNZ