There are 85 million square feet of warehouse and manufacturing space in greater Kansas City tucked neatly below ground in limestone 270 million years old.

The underground warehouses, which include two foreign trade zones, are situated on the perphery of the metropolitan area and within easy access to five interstate highways, 12 railroads, 170 trucking lines, and Kansas City International Airport. They are first-generation descendents of limestone mining operations, which continue to increase the amount of available space each year.

"We feel it's a unique and unusual kind of warehouse space," said John Harter, manager of industrial development for the Greater Kansas City Chamber of Commerce. "When we tell people about it, it causes them to turn around and say "what did you say?"

Each of the underground warehouses has economics that are competitive with above-ground facilities. Underground developers say it is 40 percent cheaper to lease their space than that on the surface and that total utility cost below ground averages about 8 cents per square foot, compared to about 50 to 60 cents per square foot above.

The underground storage units boast miles and miles of paved road constructed to accomodate fully loaded tractor trailer trucks. And one facility has enough underground railroad track to handle a 100-car freight train.

The "room and pillar" process of mining the limestone has afforded the storage areas a ceiling height of 12 feet. There is a clear space of 40 feet between the 25 feet thick limestone columns that support the ceiling. This leaves developers and renters a lot of operating latitude.

"We're into a lot of things. We have a film conversion facility, and an electronics manufacturing firm," said Gary Kelley, an executive of Great Midwest Corp., which operates one of the two underground foreign trade zones in Kansas City and has it corporate headquarters in the underground. "But the biggest users," Kelley said, "are warehousing and distribution kinds of activities."

Kelley said the underground offers several natural advantages attractive to different types of industry. The limestone provides excellent insulation for the storage of foodstuffs. Deep freeze lockers in the underground are chilled to minus 10 degrees. In the event of a power failure, the food would remain unthreatened for at least a week. (There is one report that it would take at least a year for the temperature in a locker to reach 32 degrees if the refrigeration were turned off.

One tenant, a plastic blow-molding operation, had to cool its machines when it operated above ground. But the underground 60 degree year-round temperature now eliminates the need for auxilliary cooling.

In Great Midwest's 250,000 square foot foreign trade zone, cases of sake, Soviet vodka and French wine are stacked as far as the eye can see. The company sees the foreign trade zone as a benefit for clients who normally would not use it exclusively.

"We have attracted companies, for example that dont't locate in the zone but use the zone on a limited basis," Kelley said. "That gives them the flexibility of having an economical underground space, then they have the zone to use when it's required."

Their attractive economics notwithstanding, the underground storage facilities have long suffered from an image problem: They are often mistaken for caves, complete with bats and dripping water. The underground warehouses, however, are not caves. They are manmade holes in solid limestone; they don't have bats nor do they suffer from dampness.

"We find that many people are traditionalist," Harter said. "The economics are there, but some people tend to shy away from them."

One developer actually lost a client because the man could'nt adjust to the underground, even though the client admitted the space was perfectly suited his needs.

But the men and women who work in the underground generally get accustomed to their environment in a few days. Some say they find the constant temperature especially nice, when outside temperatures register below zero or 100 degrees above. CAPTION: Picture, Underground warehouses offer natural insulation advantages, plus plenty of space in which to maneuver.