If the name “Coal Tar Dye” makes you pause for a second, the meaning, unfortunately, will not provide much relief. Coal Tar Dyes are a group of artificial ingredients consisting of colours or dyes, present in virtually every cosmetic product. Companies can produce these dyes synthetically or they can be derived directly from coal tar. If you pick up some of your daily products, especially cosmetics, you will likely see the letters “CI’ followed by a set of numbers in the ingredient list. These usually represent Coal Tar Dyes.
Each singular dye likely contains dozens, if not hundreds, of different chemicals. Since all of these chemicals are lumped into the one ingredient, there is no way to know what exactly the dye includes, meaning that some dyes are safer than others. The process of creating Coal Tar Dyes includes combining aromatic hydrocarbons. These are the molecules created by distilling something called bituminous coal. Bitumen is another word for asphalt (yes, the same material used to pave roads). Coal Tar itself is a known Group 1 carcinogen, as categorized by the U.S government, meaning it is known to cause cancer in humans. Of course, cosmetics and household products with coal tar dyes in them contain very low levels of Coal Tar. In California, products containing more than 0.5% Coal Tar must be labelled with cancer warnings. In most cases, carcinogenicity and safe exposure standards are developed for the average adult male.
Some Coal Tar Dyes are used for artificial food colouring as well. Certain dyes rejected for use as food dyes are approved for cosmetic use in products like lipsticks that we wind up inadvertently consuming.
Many Coal Tar Dyes have been flagged for review and assessment by Canada’s Chemical Management Plan. In addition to the potential cancer-causing dangers of Coal Tar Dyes, there also exists a potential for contamination with aluminium compounds or heavy metals. Both of these are known neurotoxins. Some evidence exists that artificial colours like Coal Tar dyes can increase conditions like ADHD in children, though this evidence is generally related to dyes used in food. The E.U requires warning labels on products with artificial dyes for their potential to cause learning and behavioural issues in children.
If you get your hair dyed often, watch out for the Coal Tar Dye P-Phenylenediamine, which is usually used at higher concentrations in darker hair dyes. Ask your hairdresser what type of dye they use and check out the ingredients list. The U.S National Toxicology Program and the National Cancer Institute found P-Phenylenediamine to be carcinogenic in laboratory tests and linked it to tumours in mice. However, much of the results of existing studies are contradictory, and clearer evidence is needed.
As a rule of thumb, companies that highly value and prioritize the health and safety of their customers generally steer clear from using Coal Tar Dyes. Much safer, natural, alternatives exist for products like lipsticks and foundations.
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Think Dirty Ingredient Breakdown: Coal Tar Dyes was originally published in Think Dirty on Medium, where people are continuing the conversation by highlighting and responding to this story.