Fixer is pretty benign, but still needs to be treated as hazardous waste. Keep spent fixer in bottles that are stored in the black spill tubs. There should be hazardous waste tags floating around - if not, call for more. Call the hazardous waste office to dispose of the stuff - they a bit slow in picking up stuff usually, so several calls may be needed. Give the place a clean if needed.
Dust tends to build up over time, and is a pain if left uncontrolled.
Mopping helps, as does vacuuming once in a while. You may find an inch of water sloshing on the floor, as I did once. Take out the trash to the trash room when the container gets full. You can usually find large empty trash bags lying around left behind by cleaning people. Check to see if any necessary or useful equipment is missing, or would be useful if bought.