A certificate of occupancy (C of O) is required for all "basement" apartments and that could show compliance with the minimum requirements for occupancy.
Not legal advice, I recommend you contact a real estate professional.
Douglas Elliman Real Estate
This is definitely a fire hazard since there is no way to leave the room if there is a fire in the hallway.
Are you looking at a house that is calling this basement room a bedroom?
There are many things are are illegal but are commonly done such as spitting in the street or jay walking. I am not sure if there is a specific law regarding your question, a good real estate attorney should be able to answer that question for you. If you want, give me a call and we can discuss it further and I can even get my attorney on a conference call to find out.
Even if it is legal, you have to be careful because that sounds like a potential fire hazard!!
Mitchell S. Feldman
Associate Broker/ Director of Sales
Madison Estates & Properties, Inc.
Office: (718) 645-1665/ Cell: (917) 805-0783