Developer for System z Enterprise COBOL for z/OS, Version 4.1, Compiler and Runtime Migration Guide
Freeing storage in subpools (z/OS and OS/390 only)
On z/OS and OS/390, Language Environment allocates
storage out of subpool 1 and subpool 2. VS COBOL II only
used subpool 0. If you free storage in subpool 1 or subpool 2, you can lose
data placed in those subpools by Language Environment.