About this item

Issue date:
1 November 2023
Corporate Author:
Health New Zealand | Te Whatu Ora
Environmental health

Dioxins are a group of toxic chemical compounds largely produced as by-products of combustion and some industrial processes – the polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

Dioxins are persistent environmental pollutants that exist in the environment as complex mixtures. There are a few natural sources of dioxins, such as forest fires and volcanic activity, but generally these natural sources emit comparatively small amounts of dioxins into the environment compared with man-made sources, such as some industrial processes. Cigarette smoke also contains small amounts of dioxins.

Some exposure to dioxins is inevitable because of their persistence in the environment. For most New Zealanders, about 90 percent of exposure is through diet, mainly from foods that contain animal fats, such as meat, dairy products, eggs and fish.

Many studies have looked at how dioxins can affect health, and much is still not completely understood. Dioxins can affect the growth and development of cells in ways that have the potential to result in a broad range of adverse effects. 

This document considers the literature regarding possible health impacts from exposure to dioxins – including cancer and birth defects.   


2023 revisions

The 2023 revisions are minor and administrative in nature only. The technical evidence review has not been updated from the previous edition published in September 2020.