"Black cocaine is created by a chemical process used by drug traffickers to evade detection by drug sniffing dogs and chemical tests. The traffickers add charcoal and other chemicals to cocaine, which transforms it into a black substance that has no smell and does not react when subjected to the usual chemical tests."
Source
United States General Accounting Office, "Drug Control: Narcotics Threat from Colombia Continues to Grow" (Washington, DC: USGPO, 1999), p. 5.
http://www.gao.gov/archive/19…
