The U.S. government has recently determined that Soviet authorities for a number of years have used chemical substances to monitor the activities of employes of the U.S. Embassy in Moscow. The substances in question, which have been applied indirectly to embassy personnel, leave deposits on the person or possessions of people with whom they have had contact.

The most extensively used of such tracking agents, NPPD, has been determined through biological screening tests to be a mutagen. Mutagens can be, but are not always, carcinogens in human beings. Extensive testing will be necessary to determine whether NPPD and other compounds used by the Soviets pose a threat to health, as well as to determine the extent of the embassy community's exposure to these chemicals. Preliminary indications suggest that the levels of NPPD and other substances to which individuals may have been exposed is very low. There is no evidence to date that any embassy personnel have suffered ill effects due to exposure to tracking agents.

Embassy Moscow's staff was briefed earlier this morning on what is currently known of the health implications of the Soviet Union's use of tracking agents. Unofficial Americans resident in the U.S.S.R., as well as other embassies which have been targeted, are also being informed. A special task force under the leasdership of the National Institute of Health and the Environmental Protection Agency has been established to conduct a thorough investigation into the long-term implications of exposure to NPPD and other tracking agents.

The United States deplores the Soviet Union's use of chemical substances against its diplomatic representatives in the U.S.S.R. We have protested the practice in the strongest terms and demanded that it be terminated immediately. The United States will take every possible measure to ensure the safety and well-being of all American citizens in the Soviet Union and to determine the full implications of the risks to which they have been exposed.