Locals are being urged to rethink compostable products as new research reveals hidden dangers.

With New Zealand's ban on single-use plastics, consumers have turned to compostables, assuming they're eco-friendly.

However, a University of Auckland study found many of these products contain toxic substances.

The Ministry of Environment commissioned the research to investigate how compostable items impact soil health.

The study tested ten products, including paper cups, bin liners, and pizza boxes, for harmful substances like plastics and PFAS, known as "forever chemicals."

"Consumers pay a premium for compostable products, believing they're safer for the environment," said Associate Professor Lokesh Padhye.

"However, some of these products could be more harmful than single-use plastics."

Associate Professor Lokesh Padhye says we need to be cautious about composting items with unknown chemical additives.

The research highlighted a cardboard pizza box that contained all tested chemical classes.

A fibre tray labelled 'compost me' had high levels of banned PFOA.

The study underscores the need for stricter regulations and better product testing to ensure safety.

"Many people mistakenly think home composting can handle these products," Padhye explained.

"But industrial composting, which uses higher temperatures, is often required."

The study also advocated for integrating Māori perspectives on soil health, emphasising the cultural importance of soil as an ancestor.

Padhye hopes the findings will lead to better regulations and transparency in labelling, ensuring products marketed as green truly are.