Harmless powder the KGB used in the 1980s in an effort to track Western diplomats and military attachés. Several chemicals, including nitrophenyl pentadien (NPPD) and luminol, were used against specific Westerners. When the use of spy dust was discovered, the U.S. ambassador to the Soviet Union, Arthur A. Hartman, told reporters in Moscow on Feb. 14, 1986, "We want to make it clear to the Soviet authorities that active measures against Americans in Moscow are not acceptable. " He added, "It's unacceptable to subject Americans to any outside substance. "

The previous year U.S. officials discovered that the Soviets were placing NPPD on door handles and in cars to trace the movements of U.S. officials. The Soviet government rejected the charge. (No ill effects were detected from the substances.)