The Mk 239 Is a Mk 221 fuze modified by reducing the diameter of the fuze (extending from the booster cup to the fuse threads) from 1.875" (Mk 221) to 1.59". The Mk 239 was designed to utilize stocks of Mk 221 fuzes in AN-standard GP bombs.
No information about functioning.
No information about hazardous components.
USNBD - Bombs and Fuzes, Pyrotechnics (1945)