Green’s Dictionary of Slang

(US prison) fog (which aids in escapes).

1971–2		C. Shafer ‘Catheads [...] and Cho-Cho Sticks’ in Abernethy Bounty of Texas (1990) 211: parole dust, n. – fog which aids in escapes.
2000		Other Side of the Wall: Prisoner’s Dict. July 🌐 Parole Dust: Fog.