Is it feasible that an experienced introvenous heroin addict could over-dose and die?

I have seen people boot up and and pass out in 60 seconds or less then turn blue you put a bag of ice on there balls and try to walk them around if this didnt work gave cpr till paramedics arrived and gave them narcon. They now have a tube with a narcon mist you spray up both nostrals. This is available for the general public.