Chicago city health department employees test for cyanide in Tylenol capsules and tablets using the Schonbein test whereby treated filter paper is placed in the container of Tylenol and changes color in the presence of cyanide, Oct. 4, 1982, Chicago, Il. The city began testing after the seventh life was claimed by cyanide-contaminated Tylenol. A total of 78,000 capsules and 52,000 tablets of the pain reliever have been tested and analysts have found no trace of cyanide. (AP Photo/Charlie Knoblock)