Electronics containing bromine or chlorine incinerates at temperatures below 850° C will produce dioxins and furans. Informal recycling operations generally take place outdoors, and plastic is burned at much lower temperatures unlikely to exceed 200° C. Experimental studies document that the total amount of dioxins and furans produced at lower temperatures is proportional to the material’s halogen content.

The Stockholm Convention on Persistent Organic Pollutants points out that proper management of time, temperature and turbulence as well as oxygen (airflow), by means of incinerator design and operation will help to ensure that dioxins are not released into the environment. Research has shown that even incinerators with modern flue gas treatment technologies operating at temperatures above the minimum 850° C can form dioxins when halogens are incinerated, particularly when the gases begin to cool. If the waste being incinerated contains high volumes of halogens, temperatures above 1100° C are required.

In summary, the incineration technologies and management practices required to avoid dioxin emissions are expensive and therefore not widely used.

Why phasing out bromine and chlorine?

Chlorinated dioxins and furans can cause severe health problems, including:

• Cancer
• Endocrine disruption
• Endometriosis
• Neurological damage
• Birth defects and impaired child development
• Reproductive system damage
• Immune system damage

Because dioxins and furans break down slowly, they endure in the environment for long periods of time. Like many organohalogens, they bioaccumulate in animals’ fatty tissue. The highest concentrations are found in animals at the top of the food chain, including humans. Linda Birnbaum, a leading science expert on BFRs and dioxins, led the US EPA’s 1994 Dioxin Assessment process, which concluded that for certain dioxins there was no safe level of exposure for humans.

Mixed Halogenated Dioxins and Furans

In addition to chlorinated dioxins and furans, two other forms of dioxins and furans can be formed from the combustion of electronics products: brominated and mixed chloro-bromo dioxins and furans. Although neither of these other groups of halogenated dioxins and furans has been as well studied as their chlorinated analogs, studies indicate that both brominated and mixed halogenated dioxins and furans are at least of equal concern.

It is now suspected that thousands of different mixed halogenated dioxin and furan compounds may be generated when electronics are burned. Some tests suggest that certain mixed halogenated dioxins and furans may be at least as toxic and perhaps even have greater toxicity than the most toxic chlorinated dioxin known.

Once brominated and chlorinated compounds are widely dispersed in our indoor and outdoor environments, we cannot control human exposure to them. We also lack cost-effective technologies for remediating areas that are contaminated by these pollutants. Replacing these compounds with safer compounds that do not persist or accumulate in the environment will improve the environmental footprint of electronic products.

All you ever wanted to know about dioxins...

Informative short-film about dioxins, produced by the Ecology Center of Ann Arbor for the Public Interest Research Group in Michigan, USA. The video, a 2004  interview with Dr. Linda Birnbaum, (then Director of the US EPA Toxicology Division) looks into what dioxins are, their toxicity and relevant scientific research on dioxins.

Watch the film on YouTube