How Are Hair Colours Labelled?
Permanent and semi-permanent hair dyes, which employ coal tar dye bases and coal tar dye intermediates to produce the colour, are required by law to also carry on their labels: • a warning that the product may cause skin irritation on certain individuals; • a warning not to use the product for dyeing eyebrows and eyelashes because to do so may cause blindness; and • instructions for carrying out a preliminary test for skin irritation called the patch test.
