Are the hair dyes and/or hair straighteners causing breast cancer?

Isn’t hair dead? Isn’t the scalp protected before/during the process, whether it’s dye or straighteners? How can it cause a medical problem, like breast cancer?
https://www.webmd.com/breast-cancer/news/20191204/study-links-hair-straighteners-dyes-to-breast-cancer#1

https://www.cnn.com/2019/12/06/health/hair-dye-breast-cancer-black-women-trnd/index.html