U.S. arms control negotiators learned to their surprise after the signing of the Intermediate Nuclear Forces treaty that having Soviet inspectors on U.S. soil posed problems for this country they had not anticipated.

The experience of preparing to drop 40 Soviets into Magna, Utah, was an education for the agencies involved in working out treaty details with the Soviets.The negotiators had previously been concerned with the arcane minutiae of throw weights, MIRVed re-entry vehicles and CEPs (circular error probables). A top State Department negotiator told the Deseret News a little ruefully Monday that he and his peers now realize that they need to take into account the more mundane considerations posed by Soviets walking around in the Salt Lake Valley.

The official, who spoke with the understanding that his name would not be used, said it came as a surprise to the negotiators that Hercules Inc., for example, might feel its future defense business was threatened by having the Soviet monitors living just outside its gates.

The Soviets could easily monitor more than just intermediate-range Pershing II missiles that Hercules once built. With easily available radio equipment they could eavesdrop on communications in the entire Salt Lake City area, officials have said.

They could do such things as attach bugs to vehicles that drive in and out of Hercules or other defense plants in the area, photograph antennas and other difficult-to-conceal equipment, and even try to buy secrets from employees.

The State Department official said he feels that Hercules, Morton Thiokol and other Utah contractors have been given sufficient assurance that their businesses will not be hurt by the monitoring, but he conceded that there would be costs to "harden" communications by putting in more wire circuits to replace radio hookups.

If a Strategic Arms Reduction treaty dealing with strategic, or long-range weapons is signed, and U.S. and Soviet negotiators are hard at work on one, there will be more Soviets on U.S. soil, the official said. The Utah experience, just beginning, will be a model to build upon, he said.

He said there are definitely places the United States does not want the Soviets to poke their noses - places where the United States has both strategic and conventional warfare projects, as well as plants where there is proprietary non-military work done.

A particularly difficult area is chemical warfare, he said. Verification that a nation is not making nerve gas is hard because practically any chemical plant can make militarily useful lethal chemicals. He cited one test of a commercial pesticide that could be modified for use as a weapon. Tests showed it was more lethal before being modified than afterward. Being certain that a nation was not making that chemical would be difficult.

The official told the Deseret News he did not believe further treaties could be signed and ratified before the Reagan Administration leaves office but predicted that the next president will sign treaties that bring new Soviet inspectors into the United States.