A thread can handle exceptions using the standard Factor exception handling mechanism. If an exception is uncaught the thread will terminate. For example:
[ 1 0 / "This will not print" print ] "division-by-zero" spawn
Processes can be linked so that a parent thread can receive the exception that caused the child thread to terminate. In this way 'supervisor' threads can be created that are notified when child threads terminate and possibly restart them.