“Lev Fyodorov, a top Russian chemical expert, said Freon pushed oxygen out, causing those inside to die of suffocation. He also said the scarce official information was making it difficult to understand exactly what happened on the submarine.”
Ya, suffocation.
http://news.yahoo.com/s/ap/20081109/ap_on_re_eu/eu_russia_submarine
Tell me about it. I dumped {by accident} 1200 pounds of R-11 into the bilges one day on the ship. The drain valve had rusted through and broke while I was trying to hook up a line to drop the charge on a chiller to work on it. I barely made it to a force draft vent. I'm very glad it was just R-11.