They're even listed right on the label. The Medical College of Georgia has done testing showing that SLS forms dangerous levels of cancer-causing nitrosamines when combined with several other common ingredients found in many personal care products. Your skin is the largest breathing organ of your body, and many chemicals can be absorbed through it. Nicotine and medicine skin patches wouldn't work if the skin couldn't absorb. Propylene glycol may damage cell membranes causing rashes, dry skin, and surface damage to the skin.
Ethylene glycol is first ingredient listed on the antifreeze jug.
It is because the sodium lauryl sulfate in them eats away at the mucous lining of the skin and causes urinary tract infections. Bad for little girls of any age. Do not swallow. Other ingredients may cause birth defects. By order of OSHA because a factory near there homes had a one gallon spill of a hazadorous chemical.