Can I break my lease because of an inoperable window that leads to the fire escape?

One window in my apt leading to the fire escape is inoperable, it has been nailed in place. I haven't had the issue inspected yet but I've contacted the housing inspection office and my understanding is that this violates the MA sanitary code.The property manager is aware of the issue as she noted in the lease I signed in July that it would be fixed. It has been four months and she hasn't done anything about it - can this be used as grounds to break the lease?