Among the latest substances the Canadian government recently labeled toxic are two found commonly in shampoo, personal care products and a range of items such as paints and food additives.

The substances were evaluated as part of Canada's Chemicals Management Plan. The latest assessment of 16 substances found that five pose concerns for human health and three are a concern for the environment.

Siloxanes D4 and D5 are two of the substances toxic to the environment, and are found in a wide swatch of products: shampoo, antiperspirants, lipstick, textiles, paints and coatings, sealants, plastics, non-medical ingredients in pharmaceuticals, food additives, surface treatments for wounds and more.

These two silicon-based chemicals were not found to be a concern to human health based on how much of the substances humans are exposed to, though they were found to be a danger to the environment since products that contain them are widely used, leading to high levels of D4 and D5 entering the environment. The substances persist in the environment and can harm fish and aquatic organisms.

The government aims to minimize the amount of D4 and D5 used in products and regulate the amount that is released through wastewater from manufacturing plants.

The third substance of concern for the environment is TTBP (2,4,6-tri-tert-butylphenol), a fuel additive that is persistent, bioaccumulates and harms wildlife. It will be added to the Virtual Elimination List so that the amount of it that is released into the environment is reduced below levels that can be measured.

As for the substances toxic to human health, current exposure levels to them is very low, according to the Canadian government, though regulations are being proposed for four of them so that they must undergo new assessments if they will be used in the future.

Two of the substances, epichlorohydrin and isoprene, will also be added to the Cosmetic Ingredient Hotlist and banned from being used in cosmetics. Isoprene is also used in vehicle tires, footwear and paint resins, and Health Canada is proposing that manufacturers use the best available technology to control releases of it into the environment.

The other substances declared toxic are thiourea - a substance used to make printed circuit boards - and pigments Yellow 34 and Red 104, chemicals that are used in commercial printing inks and paints.