[B. W.]

I believe a lot of the concerns over fire/explosion came from back in the day when techs used flame type leak detectors. Beyond the fire issue, most blends can create a poisionous gas when ignited. No longer an issue, everyone uses dye now. I still would not use blends, you can get all the performance you need out of 134a. The new 1234YF is flammable and expensive! Current prices: 30# keg of 134a $99.00, 1234YF $799.00. From the tech papers I've read,The main issue with 1234YF is it creates carbonyl flouride when ignited. Supposed to be worse than phosgene gas. But the upside, it's much better for the environment than 134a.