The United States continuous portal monitoring inspections were conducted at the Votkinsk Machine Building Plant, located in the Udmurt, USSR. Here Inspector Anne Mortensen operates the inspection monitoring system from the Data Collection Center.


Thirty days after the INF Treaty went into effect on June 1, 1988, the United States and the Soviet Union had the right to station up to 30 resident on-site inspectors at one former INF missile final assembly plant or INF missile production facility. Both nations did so. The United States sent its inspectors to monitor a former INF missile final assembly plant at Votkinsk, USSR, and the Soviet Union directed its inspectors to observe a former INF rocket motor production plant at Magna, Utah.

On July 2, Colonel Douglas M. Englund, U.S. Army, led the first team of 24 American inspectors to Votkinsk. On the same day, Colonel Anatoly Y. Samarin arrived in Magna with 21 Soviet inspectors. These inspectors had the right to monitor continuously--24 hours a day, 365 days a year, for up to 13 years--the missile plant's portals and to patrol the perimeter. The plant itself could not be entered.1



Perimeter road around the continuous monitoring inspection area at Magna.
  This type of on-site inspection had a special place and purpose in the operation of the INF Treaty. Article 6 stipulated that "upon entry into force" neither party shall "produce" any banned intermediate-range or shorter-range missile, missile stage, or launcher.2 To verify one aspect of this prohibition, each party had the right to station up to 30 on-site inspectors at the portals, and perimeter of a designated former INF final missile assembly or production plant. During treaty negotiations, the Soviets declared that they intended to continue producing some non-INF missiles that were "outwardly similar, but not interchangeable" with the SS-20 missiles included in the INF Treaty. These non-INF missiles, specifically the SS-25 missiles, were being assembled at Votkinsk. Soviet negotiators designated Votkinsk as the final inspection assembly plant subject to portal monitoring inspections.

When the INF Treaty entered into force in June 1988, Votkinsk was a closed city of 100,000 people located in the Ural Mountains, approximately 1,000 kilometers northeast of Moscow. Three INF missiles had been assembled there: SS-12s, SS-20s, and SS-23s. The Votkinsk plant still assembled some of the Soviet Union's most modern ballistic missiles, specifically the SS-25 missile.3

Encased in large missile canisters, SS-25 missiles were shipped from the plant in special railroad cars to operational military units. The SS-25 was not banned under the INF Treaty. However, the missile's first stage was physically similar to the SS-20 first stage; its missile canister was similar in size and weight; and its railcar exiting the assembly plant was similar to those used to transport SS-20s. The major difference in the two missiles was that the SS-20 was a two-stage missile in which the second stage was 2.87 meters long, while the SS-25 was a three-stage missile, with a second stage 3.07-meter-long.4 Given these similarities and differences, treaty negotiators had to agree upon an inspection process that would allow U.S. inspectors to be sure that no SS-20 missiles or missile stages were leaving the plant.

In Geneva Soviet negotiators proposed that U.S. on-site inspectors at Votkinsk would have the right to operate certain approved sensors and nondamaging imaging devices. These devices would weigh, measure, and image rail cars leaving the plant that were large enough and heavy enough to hold a missile container with an INF missile inside. Using these imaging devices, on-site inspectors could scan the railcars and determine the length and diameter of the missile inside its canister.5


After extensive negotiations this continuous portal monitoring inspection right was written into the treaty. In addition, treaty negotiators agreed that eight times per treaty year U.S. inspectors at Votkinsk had the right to visually inspect a missile inside its launch canister to make sure it was not a banned INF missile. The purpose of this intensive on-site inspection right was to allay U.S. concerns that an SS-20 missile might be placed inside an SS-25 missile canister. By allowing the inspecting party to randomly select and inspect a missile, with the canister cap opened, eight times a year, treaty negotiators erected a deterrent to cheating. Visual inspection of the open missile canister inside the railcar would allow the American inspector to determine if the missile was an SS-20 missile or not.6

For reasons of reciprocity, the United States designated Hercules Plant Number 1, at Magna, Utah subject to INF Treaty continuous portal monitoring inspections. The treaty stipulated that if a party did not assemble a missile with a stage that was "outwardly similiar" to a treaty-limited missile, then the inspecting party would have the right to carry out portal monitoring inspections at one "agreed" former missile production facility where INF missiles had been produced.7 Rocket motors for the Pershing II missiles had been produced at Hercules Plant No. 1 from 1982 to 1987. Reciprocal treaty rights allowed Soviet portal monitoring inspectors the right to stop, measure, and weigh all vehicles that exceeded certain dimensions as they left the plant.

By the time that the INF Treaty was signed in December 1987, both nations had designated their portal sites. Both parties had continuous portal monitoring inspection rights for 13 years, with one important reservation. If, after the end of the second treaty year, the USSR stopped assembling ground-launched ballistic missiles that were "outwardly similar" to a banned INF missile for 12 consecutive months, then neither party would have the right to conduct portal monitoring inspections. If assembly resumed, so too would the continuous portal monitoring inspections.8

At Votkinsk, the U.S. compound contained a shelter for missile rail cars that had exited the Soviet plant and were awaiting connection to the U.S. Radiographic Imaging System. This rail car will be attached to a cable and be pulled through the system.


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