Coal tar dyes are synthetic dyes, once derived from coal tar which are currently derived from petroleum sources. Coal tar dyes are used in foods, cosmetics and personal care products, such as hair dyes, shampoos and deodorants, over-the-counter and prescription drugs, and textiles. The U.S. Food and Drug Administration has been regulating color additives used in food, drugs and cosmetics since the early 1900s. - Chemical Encyclopedia
In the United States, FD&C numbers (which indicate that the FDA has approved the colorant for use in foods, drugs and cosmetics) are given to approved synthetic food dyes that do not exist in nature, while in the European Union, E numbers are used for all additives, both synthetic and natural, that are approved in food applications. - Food Ingredients & Colors
In the USA, the following seven artificial colorings are permitted in food (the most common in bold) as of 2007:
FD&C Blue No. 1 – Brilliant Blue FCF, E133 (blue shade)
FD&C Blue No. 2 – Indigotine, E132 (indigo shade)
FD&C Green No. 3 – Fast Green FCF, E143 (turquoise shade)
FD&C Red No. 40 – Allura Red AC, E129 (red shade)
FD&C Red No. 3 – Erythrosine, E127 (pink shade)
FD&C Yellow No. 5 – Tartrazine, E102 (yellow shade)
FD&C Yellow No. 6 – Sunset Yellow FCF, E110 (orange shade)
The above are known as "primary colors"; when they are mixed to produce other colors, those colors are then known as "secondary colors".
The following dyes are only allowed by the FDA for specific limited applications:
Orange B (red shade) - allowed only for use in hot dog and sausage casings.
Citrus Red 2 (orange shade) - allowed only for use to color orange peels. - Food Coloring
Reported Health Effects:
Blue #1 (Brilliant Blue)
An unpublished study suggested the possibility that Blue 1 caused kidney tumors in mice. What it's in: Baked goods, beverages, desert powders, candies, cereal, drugs, and other products.
Blue #2 (Indigo Carmine)
Causes a statistically significant incidence of tumors, particularly brain gliomas, in male rats. What it's in: Colored beverages, candies, pet food, & other food and drugs.
Citrus Red #2
It's toxic to rodents at modest levels and caused tumors of the urinary bladder and possibly other organs. What it's in: Skins of Florida oranges.
Green #3 (Fast Green)
Caused significant increases in bladder and testes tumors in male rats. What it's in: Drugs, personal care products, cosmetic products except in eye area, candies, beverages, ice cream, sorbet; ingested drugs, lipsticks, and externally applied cosmetics.
Red #3 (Erythrosine)
Recognized in 1990 by the FDA as a thyroid carcinogen in animals and is banned in cosmetics and externally applied drugs. What it's in: Sausage casings, oral medication, maraschino cherries, baked goods, candies.
Red #40 (Allura Red)
This is the most-widely used and consumed dye. It may accelerate the appearance of immune-system tumors in mice. It also causes hypersensitivity (allergy-like) reactions in some consumers and might trigger hyperactivity in children. What it's in: Beverages, bakery goods, dessert powders, candies, cereals, foods, drugs, and cosmetics.
Yellow #5 (Tartrazine)
Yellow 5 causes sometimes-severe hypersensitivity reactions and might trigger hyperactivity and other behavioral effects in children. What it's in: Pet foods, numerous bakery goods, beverages, dessert powders, candies, cereals, gelatin desserts, and many other foods, as well as pharmaceuticals and cosmetics.
Yellow #6 (Sunset Yellow)
Caused adrenal tumors in animals and occasionally causes severe hypersensitivity reactions. What it's in: Color bakery goods, cereals, beverages, dessert powders, candies, gelatin deserts, sausage, cosmetics and drugs. - Mercola