Back in the 70's one of my brothers and I worked in the J&L steel mill in Pittsburgh PA during the summers to earn enough money to pay for our college tuition and books. I have worked in the south side open-hearth, the south-side boilers steam plant, the rolling mill, the blast-furnace, and the coke-ovens. A lot of hot hard work, some of it quite dangerous. In the coke-ovens during the summer everyone wore cotton long-underwear under their green flame-retardant work clothes. It was soooo hot that after ten minutes the long-underwear would be soaken wet with sweat and the sweat evaporating from the long-underwear next to your skin would keep you cool. It was soooo hot ontop of the coke-ovens that we had to wear wooden saddles under our work boots because the hot brick surface we walked on would melt the soles of our work-boots without the protection of the wood.