Dioxins and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) that can accumulate in the food chain, especially in the fatty tissues of animals, leading to human dietary exposure to these toxic chemicals. Although their presence in food and feed have gradually decreased over the years as their use by industry has been reduced or phased out, dioxins and PCBs still linger in the environment, and therefore, in food and feed.

In a new, draft scientific opinion, the European Food Safety Authority (EFSA) suggests lowering the tolerable weekly intake (TWI) for dioxins—specifically, polychlorinated dibenzo p-dioxins and dibenzofurans (PCDD/Fs)—and dioxin-like polychlorinated biphenyls (DL-PCBs) to 0.6 picograms per kilogram of bodyweight (pg/kg BW). The existing TWI established in 2018 is 2 pg toxic equivalents (TEQ)/kg BW.

Based on the latest dietary exposure estimates from European countries, EFSA believe that the new TWI is exceeded in all age groups. A balanced and varied diet, however, can help reduce the risk of exposure to contaminants, says EFSA. Including a wide range of foods in the diet may lower the intake of dioxins and PCBs from any single source.

EFSA was asked by the European Commission to revisit its TWI for dioxins and PCBs considering the new World Health Organization (WHO) toxic equivalency factors (TEFs) for chlorinated dioxin-like compounds, which were revisited in 2022 and resulted in the TEFs for many PCDD/Fs and DL-PCBs being changed. These TEFs are internationally used values to express the toxicity of dioxins and dioxin-like PCBs relative to the most toxic form of dioxin (2,3,7,8-TCDD). Also in 2022, to protect public health while WHO’s work was underway, the EU set maximum levels for dioxins and dioxin-like PBCs for foods that had not yet been covered by legislation.

PCBs were once used widely in electrical equipment, heat transfer systems, and hydraulic systems, as well as other applications. PCDD/Fs have no use themselves, but are generated as byproducts of thermal and industrial processes, such as the incineration of flame-retarded plastics, especially at electronic waste sites. Dioxins and some PCBs (i.e., dioxin-like PCBs) that have similar toxicological properties are often considered together within the context of public health.

Long-term dietary exposure to dioxins and PCBs can affect the immune, nervous, and endocrine systems, and cause reproductive harm.

EFSA’s latest draft opinion reaffirms that dietary exposure to dioxins and dioxin-like PCBs is a health concern.

A public consultation on the draft scientific opinion is open until January 26, 2026. The opinion can be viewed via the consultation page.