Mr. Cunningham. Yes, or an area of the cast. The theory of the test is that it is a test for gunpowder residues. Now, that is the theory, and it is fallacious, inasmuch as the reagents used in these two tests are not specific for gunpowder residues. Now, it is true that the nitrates and nitrites in gunpowder residues will react positively with diphenylamine and diphenylbenzidine, but they are not specific. They will react—these two reagents will react with most oxidizing agents.
Mr. Eisenberg. Can you give us a few examples?
Mr. Cunningham. Yes. Urine, tobacco, cosmetics, pharmaceuticals, soil, fertilizer—I have a list here of the different families or classes of compounds that will react.
In addition to nitrates and nitrites, substances such as dichromates, permanganates, hypochlorites, periodates, some oxides, such as selenium dioxide and so forth. Also, ferric chloride and chromates and chlorates. The list of oxidizing agents is so large—that will react—that you cannot specifically say it was a gunpowder residue.
Mr. Cunningham. Supposedly it is to determine whether or not a person has fired a weapon. In actuality, in chemistry it is a good indication that an oxidizing agent is present. The reagents have a valid use in a chemistry laboratory.
Representative Boggs. Let me put the question this way. Given a dozen ordinary people in the ordinary walk of life, what would be the chance of a positive reaction on any one of these 12 people?
Mr. Cunningham. Excellent, sir.
Mr. Eisenberg. Has the FBI performed an experiment to determine this?
Mr. Cunningham. Yes; we have. The early sets of tests we ran with diphenylamine. And 17 men were involved in this test. Each man fired five shots from a .38 caliber revolver. Both the firing hand and the hand that was not involved in the firing were treated with paraffin casts, and then those casts treated with diphenylamine. A total of eight men showed negative or essentially negative results on both hands. A total of three men showed positive results on the idle hand, but negative on the firing hand. Two men showed positive results on their firing hand and negative results on their idle hands. And four men showed positive on both hands, after having fired only with their right hands. That was the first test we ran.
The second test—we used people who had not washed their hands in any way. They were going about their duties during the day. Their hands were soiled. Nine people fired weapons out of 29—20 people just had the casts made.