Green’s Dictionary of Slang

1. (drugs) phencyclidine.

1979		H. Feldman et al. Angel Dust 124: The large number of street names it has been accorded over the years: [...] ozone.
2003		Microgram Bulletin XXXVI:8 182: On the street, PCP is commonly referred to as [...] Ozone.

2. marijuana.

2001		ONDCP Street Terms 16: Ozone — Marijuana, PCP and crack cigarette; marijuana cigarette; PCP.
2003		see sense 1.