The BLP option is associated with job class; that is, the installation has the option to allow or disallow BLP by job class. It is recommended that BLP be disallowed completely, or if this is not possible, that one job class be set aside as the "BLP" and controlling class. This can be done by using JES initialization options to allow BLP for only that controlling class and by using installation JCL exits to force TYPERUN=HOLD for all jobs specifying that class. The system operator can then monitor that class and release only jobs authorized to use BLP. For the method of specifying BLP for the JES reader, see z/OS JES2 Initialization and Tuning Reference.