I am building a darkroom in my basement. I plan to use a positive ventilation system, but my worry is with the outgoing fumes. The darkroom is in a large storage area, inside of the basement. About 30 feet away, in a different storage area, is the house's furnace. Also, our cat spends a lot of time in the basement (but not in the large storage area). I am worried that the fumes will leave the darkroom and go into the storage area. Where the storage area meets the finished basement, there is a 1 or 2 foot gap between the basement's drop ceiling and the storage rooms ceiling (storage room ceiling is higher than basement ceiling, and the gap is open). Will the fumes leave the storage area and linger above the drop ceiling? Do I have to worry about some of the fumes coming in contact with the furnace? Basically, I am worried that the fumes will leave the darkroom and spread into the basement harming my cat or making the basement air smelly or unsafe. Is my concern valid, or will the fumes dilute enough. Thanks a lot for your help, I appreciate it... (and thanks for the great community).