Extensive tests by U.S. officials have proved that the chemicals the United States says the Soviet Union uses to track the movements of American officials here are harmless, according to a statement released by the U.S. Embassy here today.
The conclusion allays fears that arose in Moscow's American community last summer when U.S. officials here and in Washington first raised the possibility that the tracking powder, familiarly called spy dust, might cause cancer.
Several chemicals, including nitro phenyl pentadiene, or NPPD, and luminol, are used "against a specifically targeted, relatively small percentage of official American employes," the embassy statement said.
The employes affected "have contact with Soviets," U.S. Ambassador Arthur A. Hartman told reporters, but he declined to identify them further.
Hartman said in a press briefing, "We want to make 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."
Soviet officials in Washington were informed of the conclusions, Hartman said.
Last August the U.S. government protested that Soviet agents were using NPPD on door handles and in cars to trace the movements of U.S. officials.
The Soviet Union flatly denied the charges. Soviet officials described the spy dust accusations as an attempt to poison U.S.-Soviet relations before the summit meeting last November.
The tests, conducted by officials from three U.S. agencies, revealed that "exposure to the quantity of NPPD found does not pose a health hazard," and that even if it enters the body there is little or no retention after 48 hours.
Researchers from the National Institute of Environmental Health Sciences, the Environmenal Protection Agency and the Centers for Disease Control came to the Soviet Union in August and September.
After the spy dust problem was identified in August, visiting EPA staffers inspected the homes, cars and offices of 20 percent of the Americans living in Moscow and Leningrad. Altogether, they sampled 418 surfaces. But no traces of the chemical NPPD were found, the statement said.
Hartman, dissatisfied with the results, ordered another inspection last month, which resulted in traces of NPPD being found in five vehicles used by U.S. employes. The chemical appeared to have been sprayed into the vehicles, Hartman said.
Hartman said the research process resulted in a more simplified way of detecting the substance, which was previously only possible with the use of a mass spectrograph.