There are over 80,000 chemicals on the market in the US, and the Environmental Protection Agency has only banned nine.
The EPA has had the power to regulate harmful chemicals under the Toxic Substances Control Act (TSCA) since 1976. But it has actually used this power only a handful of times.
This is partly because the TSCA makes it pretty difficult for the EPA to regulate industry. The law only lets the EPA test a chemical to find out if it is toxic if companies have already shown the agency that the substance causes harm.
Of course, companies aren't exactly motivated to tell the EPA that one of their products is harmful — they want to make a profit, not create more regulatory hoops to jump through.
These are the five existing chemicals that were around before the Act went into effect that the EPA has deemed harmful, plus the four new chemicals that came on the market after TSCA and have since been banned.
Most of them have really long chemical names, so we've also included what they were used for and how they can be toxic.
1. Polychlorinated Biphenyls (PCBs)
The EPA banned PCBs in 1978 because they are toxic to humans, animals, and some plants, and they build up in the environment.
Studies showed that they could cause cancer in mice and rats.
PCBs were mostly used in electrical equipment, transformers, and hydraulics, but also in applications like plasticizers and fire retardants.
2. Fully Halogenated Chlorofluoroalkanes
These chemicals were a major part of aerosol sprays, until we figured out they were depleting the ozone layer.
They were also popular in air conditioning units, refrigeration, fire suppression, and insulation.
The EPA banned Fully Halogenated Chlorofluoroalkanes in 1978 to help protect the ozone layer, which shields us from harmful UV rays that can cause skin cancer.
3. Dioxin
The EPA banned dioxins, an extremely harmful class of about 75 chemicals, in 1980.
One of the worst of them, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), was used as an herbicide, and an ingredient in Agent Orange, which US troops sprayed during the Vietnam War.
Some dioxins can also be a byproduct of burning pulp to make paper, and of burning trash.
Dioxins in high quantities can cause cancer, and they have been linked to reproductive issues, developmental problems, and immune system damage.
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