Hi PeterM306;
Welcome to the forum.
The seal can be replaced, but it may depend on what model smoker your have, and if that model is still supported, and parts are available.
Yard & Pool has a door seal for the BS815XLT
BS815XLT Door SealThe Bradley website doesn't list many parts so you may have to contact them for a replacement.
If your door seal actually melted, then you may have a bigger problem with your smoker. It should not have gotten that hot to melt the seal, unless you had a fire.
Most likely, if you haven't been cleaning your seal, and the area that it comes into contact with the smoker; smoke residue will build up. When this happens the seal will stick to the smoker cabinet, and when the door is opened the seal will rip away from the door. You should periodically (or even after each smoke) clean those areas with isopropyl alcohol. Some members state that warm soapy water works just as well.