Chemical Smell Predicament

I’ve been living in an older apartment in Ohio for two years now, and have noticed an intermittent chemical smell for the duration of that time. I had originally tried to report this maintenance when I first moved in, but had described the smell as “like gas”. I don’t have a gas line, so I got told to open a window, I was probably imagining things. I felt stupid. Maintenance additionally drove up to my apartment the next day, but never got out of their car and marked my order as met. Well, it never went away, so I tried to report it again recently. I said there was a bad smell coming from either the AC or the water tank. They decided to replace my water tank, but the smell is still there. It is potent enough at times that I know it can’t be good to breathe long term. I haven’t had really any symptoms related to breathing chemicals so I don’t really know what to do. A friend suggested it might be Freon, but I feel like maintenance is going to be pissed at me if I make another request this soon. Is there something I can do to figure out what it is? I don’t know how to deal with this.