I can't call anyone a liar that says ZC is OK for steel because I don't know but this is the first I've heard of it being used on steel. I DO know that, as noted above, it's been used on aluminum for decades and yes it's bad stuff if you breath it in, both fumes and particulate. MEK is also bad stuff. Short term it'll dry up & crack your hands real bad. Long term it'll screw up your innards. It does penetrate your skin so wear chemical gloves if you do use it. FYI, in case you consider using alodine as a corrosion inhibitor, never, EVER, let MEK come into contact with alodine. That includes rags contaminated with each.
