When the prison was first refurbished in 1933, only B and C blocks were fitted with tool-proof steel bars. These A-Block cells and those in D-Block were not.
For reasons unknown, the prison management chose to use these cells as holding cells for the most violent and otherwise demonstrative prisoners. The strap steel bars were easily cut by Henry Young and other participants in the 1939 escape attempt.
After the upgrading of D-Block, A-Block was used only for storage.