From that other thread? It was Webac 151 resin with 15X accelerator mixed at 10% by volume, not something most people will ever bump up against. This product is used for high pressure chemical grouting of cracks in concrete structures, for waterproofing purposes. It was messy and inconvenient (!) but not terribly hazardous. The cured foam is chemically inert, sufficiently that the product is certified for use in potable water systems. MDI's are only of concern during cure, and that takes only seconds. I hosed it down with water to intentionally accelerate the reaction and minimize skin contact, and finished out the day, working for 3 more hours before returning home.

Still, the stuff has an uncanny ability to catch you with your guard down. I was working in a computer chip plant clean room once, dressed up in a bunny suit, full hood, booties, 2 sets of gloves, surgical mask, plastic glasses AND a full-face shield, and an assistant similarly decked out. No skin showed at all except 1/4" around the plastic glasses. She had to sneeze, and at that particular moment, well, you can guess the rest. She was a good sport about it, though. We are still married (to each other) after all these years. I love her to death, and if it's Celtic knotwork she wants, it's Celtic knotwork she gets.