Required Egress Question

Is a roof ladder and hatch considered a method of egress in a building? I am looking at a 4 unit building where the top floor renovation incorporated the roof ladder & hatch into the apartment. There is a sprinkler system in place. I can’t find any permits for work done in the building on the DOB website and think it was probably done a while back without permits. To be up to code, would I have to restore the access to the ladder (from the public staircase)? I can’t imagine the (RS) tenant would be too happy about that! Anyone have an experience with this kind of situation Thanks as always….