Welder here. Aluminum oxide inhalation is correlated with an increased risk for alzheimers, not cancer. Hexavalent chromium is a carcinogen, and that comes from heating up stainless steels. So you are actively replacing a relatively non toxic oxide with the potential for an actually toxic carcinogenic gaseous metal, assuming your pocket knife is some sort of stainless steel (statistically very likely).
You can’t argue that 40k panders to the LGBT crowd because fuckin obviously if you’ve ever even looked at a 40k title, but you also can’t really argue that 40k isn’t at least a little sexual.
You got ratlings, pretty much everything slaanesh, aeldari waifus, and the entire Ciaphas Cain series. And while yeah, you don’t exactly get steamy love triangles in mainline 40k lore, you also have callidus assassin’s and sisters of silence popping up all the damn time. Sex isn’t the focus (mostly. Looking at you ciaphas) but it’s certainly present in the setting.