I'm coming to the end of twenty+ years with a natural gas utility company, and a safety-related issue that was pounded on for my whole career was, "stay completely away from any synthetic materials whatsoever." Our coveralls were 100% cotton, as were the outer shells of the fire resistant jackets we were issued.
One year we had a safety stand-down at work, and spent eight hours on safety-related issues. At the end of the day, they handed out brightly-colored tee-shirts with the company logo and a safety slogan on them. Shirts made of 100% Rayon - which is extremely flammable, and melts and clings to your skin in the event of a fire....