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Persistent Pollutants

2 plastics additives, insecticide face global ban

Parties to the Stockholm Convention agree to list the substances for elimination

by Britt E. Erickson
May 12, 2023

A worker recycles electronics waste.
Credit: PradeepGaurs/
Recycling electronics waste can expose workers to Dechlorane Plus and other toxic substances.
Chemical structures of UV-328 and methoxychlor.

Delegates from around the world have agreed to add two plastics additives and a pesticide to the Stockholm Convention on Persistent Organic Pollutants, an international treaty that lists toxic substances for global elimination. The agreement was reached during a 2-week meeting that wrapped up May 12 in Geneva, Switzerland.

The two plastics chemicals are the flame retardant Dechlorane Plus and the ultraviolet stabilizer UV-328. The targeted pesticide is methoxychlor. All three chemicals meet the criteria for inclusion in the treaty: they are persistent, bioaccumulative, and harmful to human health and the environment, the delegates found.

Environmental advocates welcome the decision to add the three chemicals to the Stockholm Convention, but they point out that exemptions will allow continued use of the plastics additives.

The agreement is an important step “toward protecting human health and the environment from three chemicals linked to serious health conditions and threats to biodiversity,” Sara Brosché, a science advisor with the International Pollutants Elimination Network (IPEN), says in a statement. “But we are disappointed that financial interests caused unnecessary and dangerous exemptions that will lead to ongoing toxic exposures, especially for waste workers and communities in low- and middle-income countries where plastics and other materials containing these chemicals often end up.”

During the Geneva meeting, IPEN released a study showing high levels of Dechlorane Plus in the blood of electronic-waste recyclers in Thailand. The flame retardant is widely used in electronics and automobiles. When such products are broken down for recycling, workers are exposed to high doses of the chemical, the study finds. Dechlorane Plus is associated with reproductive and neurodevelopmental disorders.

UV-328 protects polymers from breaking down under ultraviolet radiation. The chemical is linked to adverse liver and kidney effects in animal studies. UV-328 is the first nonhalogenated chemical to be added to the Stockholm Convention.

Labeling of products that still contain the two plastics additives remains a sticking point. The convention’s scientific review committee plans to evaluate options for identifying the substances in products and waste.

Negotiations on methoxychlor, an organochlorine pesticide, were much less contentious than those for the two plastics additives. Delegates agreed to add the insecticide to the Stockholm Convention without exemptions.

Methoxychlor was once used to combat numerous insects on crops, ornamentals, livestock, and pets. It is banned in the US and the European Union because of its toxicity, persistence, and ability to bioaccumulate.

The US has not ratified the Stockholm Convention, but it participates as an observer in meetings. The Geneva event was held together with meetings of the parties of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal and the Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and Pesticides in International Trade. The three international treaties aim to improve management of chemicals and waste.

The Stockholm Convention is the only one of the three treaties that eliminates or restricts the production and use of chemicals. The Basel Convention focuses on identifying hazardous substances in waste. The Rotterdam Convention focuses on hazardous substances in international trade.


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