Taking the original question in a context I think it was meant to be taken (which I am assuming basic B&W work without exotic processing or toning)....
There is nothing in basic BW chemicals that are dangerous or risky in a sense that touch or smell in duration that will take to complete the process will cause explosions, illness, or death. If you consume large amount such as eating or drinking them, or, if you are somehow sensitive to the particular chemical component, you may have problems but that is true to just about anything. Typical household chemicals such as toilet bowl cleaner, bleach, hair sprays, nail removers, paint thinners, and rubbing alcohols are far more risky.
Is it smelly? Not really. Developers I use are almost scent-less. Stop bath smells like vinegar. Fixer smells like very light acid. I also do some processing in a bathroom. A quick wipe will eliminate all traces of chemicals for me.
However, basic precaution is warranted. For example.... I never bring any food or drink into darkroom for I may mistaken chemical bottles in careless and mindless moment. I always clean up after working. I never use containers that could be mistaken for anything else for storage. While there is no children in a house, there is one dummy I cannot eliminate. ME!
Even now, area high schools and middle school actually teach and let students process films and prints.
