So its getting really bad actually.

Well over a decade ago, it was paint huffing. If we had an unconscious teen we always checked the inside of his/her shirt or jacket looking for the paint residue that they had wiped off. The affinity for gold paint made that one easy

With Nitrous its harder and it almost always a typical secondary discovery when whippets are found near them as the serum half life in 15 minutes at most and a bit longer in hard core users so blood testing is out

also looking at the tanks they do not have a regulator on them and those tanks are under a lot of pressure. I will not bore you with a lecture on gas laws as there at several at work here (I know right in physics I was one of those "why TF do I need to know this shit", turns out anytime I fly with a patient) those appear to be 640g tanks. That will expand significantly (same tank of o2 will expand to about 440L of gas) under pressure and at freezing temps. That can do significant lung damage