I love this photo. the colors are spectacular. This is one of those shots where blown up big you get the feeling you could just walk right in. I say Wallpaper for this!! :)
There is a public housing facility in Rockford ILL that has a similar round design. If you wander downtown New York one of the old hospitals was designed with all round rooms too. I the early 1900's ish it was believed that the round rooms prevented disease by limiting the places that germs could settle, they made a come back again in the 50-70's in some areas, but they always make for odd layouts.
I was surprised to see this place on your list as I toured the facility when it was still open. I went to High school in Michigan and one of the teachers I had was a psychologist who had practiced for years and had admitting privledges in at this facility up until like 1998.
I often take chalk when I go into abandoned places... I will use it to mark where I have been and try to leave behind inconspicious markings to warn others if areas are unsafe by using different colored chalk to mark my path.
Freon wasn't invented until 1928, prior to that most refrigeration was done with pressurized ammonia, methyl chloride, or Sulfur dioxide which were all pretty nasty chemicals. DuPont owns the patent for Freon and it wasn't used in self contained cooling units until the early 1930's by Carrier. As someone from the company stated this was probably loaded with ammonia but the other chemicals they used to use are far more insidious and nasty to inhale so if you run across more like I'd steer clear of playing with knobs. (Not to mention the danger of old pressurized items to begin with.)
Actually the syringe isn't that old a lot of them are color coded by the manufacturer based on size in cc's. The greater worry from needles is probably Hep C more than anything else and a lot of junkies use in secluded places for various reasons. Drug culture is something I have grown up with and for better or worse there is a specific mentality that comes with it that can be very disturbing and hard to understand in the greater community. If you see burned soda can halves laying around along with the needles, than it is time to really worry.
Blessed Be
Uncle Steve