To be honest, I am also unaware of that. But, since we're talking about chemicals, did you know that the (TSCA) regulates their introduction?
Some do but thankfully there's the TSCA or Toxic Substances Control Act which helps protect consumers against dangerous chemicals.
I love to color my hair. I recently colored it purple. How interesting! Did you do it yourself or did you go to a professional? I did it myself at home. Do you have any advice on how to maintain it? I don't have any advice. What I can tell you is that in 2011 alone, at-home coloring in the US reached 1.9 billion dollars. Wow, that's a lot of money. It can be stressful dying your hair by yourself. I wonder how they dyed it in ancient times. That is something I also can't answer. If it helps, I know that there are natural dyes from plant sources Wow, that's probrably safer than putting a bunch of chemicals in your hair. Do the chemicals in modern hair dyes have any adverse effects?
The Toxic Substances Control Act (TSCA) is a United States law, passed by the United States Congress in 1976 and administered by the United States Environmental Protection Agency, that regulates the introduction of new or already existing chemicals.