what to do about someone smoking on oxygen

I wrote a question about this a couple of wks ago, a new guy that moved into my bldg is on oxygen and constantly smoking, and i mean constantly, hes outside from morning till nighttime, literally, ive seen him out the window and everytime i go somewhere and back hes still smoking, i know sometimes he might take his oxygen off but othertimes leaves it on, i did tell my apt manager about it and hes talked to him but thats about it, hes a fire waiting to happen, thought of calling the police but im afraid of people getting too mad at me for it and wasnt sure if they would do anything, who else can i report it to, im afraid of reporting it cause i might be facing angry people afterwards but what if he starts a fire, wonder what he'll do in the wintertime if he cant smoke outside, thought of the health dept, my manager is too nice to do anything about it, should i talk to the fire dept or whom, any suggestions? makes me paranoid that my smoke alarm might go off anytime,