Illegal extra bedrooms?

[David S.]

Was looking at a property recently, and spoke with the seller's agent. He said some of the tenants of the duplex are sleeping in the basement, which has no egress windows. No egress at all, except the stairs to the main floor. 

I'd be concerned for their safety to start out with. It does raise a question though - what are the legal requirements of the landlord? If I purchased the property and knew, or had a reasonable suspicion, that tenants were living in the basement could I be liable?