Actually they and the Beech 1900 don't really have doors, just dividers. That is a huge concern among flight crews and the answer is no one really knows. Its like teh double or stronger doors. Everyone is in favor of it, but in a lot of planes there just isn't room for them, the EMB-120's door can't be closed when there is a jump seater and the SF340 and CRJ couldn't fit another door or even that much thicker of one. It is a tough fix in a lot of planes and someone is going to need to come up with a good diea real soon.