I saw this movie back in the 80s when I was a little kid but it could have been made in the 70s I guess.  It seemed to be a sci-fi/horror type.  It was about a red mist of some sort that would kill people when they were secluded from everyone.  There was a scene in the bathroom where it killed someone.  It took place on a military base or a boat, some place that the people in danger could not get away easily.