One of Johnson County’s hidden gems isn’t in a jewelry vault. It’s buried about 80 feet underground just southwest of Interstate 435 and 95th Street in Lenexa. Your map to that buried treasure starts with a couple of small blue roadside signs heading west on 95th. The only word — Meritex — is scant clue that down a winding two-lane access road is a bustling industrial city that daily swallows 600 workers into a former limestone mine. One of those workers is John Clune, president of the aptly named Cavern Technologies. His company logo hints at the unusual location for the sophisticated computer data storage business: “We set IT in stone.”

Stone indeed. Massive pillars left behind after mining ended in 1988 anchor the corners of Cavern Technologies’ space. It’s a location that works for Clune.

“The caves are dry. We’ve got protection from natural disasters like tornadoes and ice storms. We have controlled access. We’re secure. And we save a lot on heating and cooling costs,” Clune said.

Winter or summer, the underground temperature hovers at 68 degrees.

For all those reasons, the Meritex underground is home to 35 tenants that store documents; make boxes, envelopes and furniture; warehouse liquor; distribute snack foods and more.

“When it’s raining or snowing or 100 degrees, our route drivers are very comfortable loading up their trucks at our inside docks,” said Canteen district general manager Frank Merrick with a smiling emphasis on very .

Many residents know that the Kansas City area is famous as the world’s No. 1 location for the re-use of mined-out caverns. Thanks to geology that blessed it with sturdy layers of Bethany Falls and Argentine limestone, the rock was heavily excavated for construction and product-additive uses. Left behind was redevelopment opportunity.

Today, there are a dozen major underground business complexes in the metro area and a score of smaller caves with other uses. Meritex Enterprises operates Johnson County’s only entry among the major developments. All told, the area’s subsurface industrial parks occupy than 20 million square feet — or about 10 percent of all the industrial space in the metro area. Meritex has developed 2.25 million square feet in Lenexa, and it has about 1 million more ready for expansion.

Like the area’s largest underground development, the Hunt Midwest SubTropolis northeast of downtown Kansas City, Meritex is a “premier” one, said Jill McCarthy, vice president of business development at the Kansas City Area Development Council, an official commercial booster for the metro.

“The good ones take backup power, ventilation and fire-suppression seriously,” she said. “When they’re done right, we’ve had clients go, ‘Oh my gosh, this is a great option.’ Especially when it’s freezing or 100 degrees out, the underground fares well (among prospective clients) compared to standing outside and looking at dirt in an undeveloped above-ground office park. … It’s not for everyone, but it works for more than not, and it’s definitely an asset for us to promote.”

The concerns about backup power, ventilation and fire suppression are serious. One of the metro area’s undergrounds, the AmeriCold refrigerated facility in Kansas City, Kan., had a fire that started in late December 1991 and took four months to burn itself out. It destroyed about $500 million worth of food, paper records and other goods. There was no sprinkler system. Smoke and lack of alternate access routes made it impossible for firefighters to extinguish the fire.

“AmeriCold was a good lesson learned,” said Marty Quick, division chief for prevention in the Lenexa Fire Department.

Quick complimented Meritex for its “aggressive” policing for hazardous materials and for routinely checking fire suppression equipment. The department also inspects the underground development annually and trains its firefighters down in the complex to be familiar with its layout.

“We have a specific strategy for handling any fire that might happen there,” Quick said.

After the Meritex business park opened, the Lenexa department bought a high-volume fan mounted on a trailer that can be hauled into the underground to direct smoke to ventilation outlets. And it purchased advanced communication radios that operate underground, unlike regular equipment.

Fortunately, “we’ve never had to fight anything there except a small overheated motor on a machine or a truck fire, and they were kept in check by the systems that operated as designed,” Quick said. “I wish all our management partners in our city were as proactive as Meritex.”

Bill Seymour has had a career in Kansas City’s undergrounds. He came to manage the Lenexa facility after helping the Minnesota-based McNeely family, owners of Meritex, acquire the property in the 1990s after the limestone mining had ended. The family was no stranger to subterranean development, having first entered the industry in the 1960s.

There’s plenty of underground competition for tenants in the Kansas City area, Seymour acknowledged. But because of Meritex’s unique Johnson County location — the other complexes are in Wyandotte county or on the Missouri side of the area — he said Meritex’s competition is more above than below ground. (The company also owns the land above the underground and is developing that as well.)

“Our basic lease rates run between three and five dollars per square foot per year on a gross, which includes real estate taxes and common area maintenance expenses,” Seymour said of the underground. “The rates for Lenexa area surface buildings would comparably be four to eight dollars per square foot.”

Another edge for the underground: “Our utility expense runs between 25 cents and 30 cents per square foot compared to about one dollar per square foot for surface,” he added.

Seymour said tenants also like the nearby highway access to I-435, I-35 and U.S. 69.

Anyone who participated in last year’s Jingle Bell Run/Walk, an annual benefit for the Arthritis Foundation, likely used one of those arteries to reach the Meritex underground. When there, they saw its warren of concrete roadways, its 16-foot-high ceilings, and, most of all, its massive white-painted natural limestone pillars that dot the space.

The square pillars — about 25 feet on a side and spaced about 35 feet apart — are the distinctive feature of underground industrial parks. To section off tenant space among the pillars, concrete blocks and wallboard are chiseled to nestle tightly against the erose rock.

What all those the runners and walkers likely didn’t notice were the security and utility systems that attract many of the tenants.

Visitors to Cavern Technologies’ data center get a full helping of the underground security. Video surveillance cameras keep watch. Pass codes are required to enter specific spaces. And, sometimes, biometric or face recognition software verifies users who are permitted access to sensitive client computer rooms.

“One of our clients has $10 million worth of equipment here,” said Clune. “It’s a discreet space with controlled access, a good place for mission-critical operations.”

Down sterile halls and behind series of locked doors are the computer nerve centers for such clients as BlueCross BlueShield of Kansas City. One of the largest spaces houses equipment and offices for the Sisters of Charity of Leavenworth Health System. Few client staff members are required to be onsite; most of the operations are handled remotely.

Computer safety and power backup are essential in today’s business world, said Kevin Fleming, communications manager for Cavern Technologies, which expects $5 million in revenue this year. Last year, the company grew 100 percent.

“After the tornado in Joplin, we acquired a few more clients,” Clune said.

Fiber carriers AT&T, TWtelecom, CenturyLink, SureWest and Time Warner Cable Business Class serve Cavern Technologies’ clients.

Speaking of security — visitors can’t even get in the door of Meritex’s largest tenant, a Federal Records Center of the National Archives and Records Administration. It’s closed to the public, fitting for an agency that bills itself as “The Secure Choice.”

The Lenexa underground, which employs 51 people, is one of 18 federal records centers nationally that are used by about 400 federal agencies to store records, pull them when needed and, eventually, recycle or archive them. Three of the centers are in Kansas City area undergrounds. At Meritex, the second-largest of all the national archives agency’s records centers nationally, it has the capacity to store 3.6 million records boxes in 784,000 square feet.

But, sorry, “Raiders of the Lost Ark” kind of photos aren’t permitted. Another interesting thing we can’t photograph at the Lenexa site is a cold storage area where motion picture film is kept for the National Archives.

The National Archives and Records Administration’s biggest customer in Lenexa? The Internal Revenue Service. Next biggest? The Bureau of Indian Affairs.

David Weinberg, Federal Records Center program director in Washington, said locating in limestone caves is a win-win-win. Rental space is low cost, a win for taxpayers; records preservation is easier because of temperature and humidity controls, a win for history; and the temperate environment is a win for staff, who don’t have to do physical labor in hot or cold above-ground warehouses.

There’s no windshield scraping on icy days, Weinberg noted, touting the benefits of underground parking.

Working underground clearly has its cheerleaders. But it also gives some people heebie-jeebies. Jon Robichaud, operations manager at Priority Envelope Inc., said a handful of potential employees over the years have decided the environment wasn’t for them.

“A few have said they’re claustrophobic, but it doesn’t take much getting used to for most people,” he said. “We sometimes do ask delivery drivers what the weather is like ‘out there,’ but mostly we don’t think about it.”

Robichaud said he has to look at one of those big white rock pillars to remind himself that he’s underground. He works with a staff of 26 that’s spread over three shifts a day, Monday through Friday, making every kind of envelope imaginable. The company has been in the Meritex underground since 2006 and just renewed its 36,000-square-foot lease.

“Sixty-seven degrees all year long and humidity is no problem — a perfect atmosphere for paper,” Robichaud said.

The biggest environmental drawback is noise in the shop. Workers have a choice of three different kinds of ear plugs, and it only takes few seconds to see why they’re needed when standing in between a rock pillar and a giant machine that spits out 20,000 envelopes an hour.

Truth be told, there is another thing that bugs some employees in the underground: No cell phone reception. It’s not uncommon to see workers using their breaks to stand at the big tunnel entrances and make calls. On the flip side, some employers see lack of cell phone reception as a productivity plus — employees aren’t spending work time on their phones.

Near Priority Envelope, in a 50,000-square-foot space, a semi-truck-sized machine churns out muffin boxes and other heavy paper and cardboard packaging at Service Pak.

Supervisor Wayne Shanks said seven employees work Service Pak’s two shifts, which run 10 hours a day, four days a week. It’s an efficient combination printing, packaging, storing and shipping operation unaffected by the weather.

And that, again, is the major draw for Canteen, which has been in the Lenexa underground for three years.

“We came from an outdoor building just off 31st Street and Southwest Boulevard,” said Frank Merrick, the district general manager. “We’d had theft problems from our warehouse. We had to be careful about when we loaded our delivery trucks. On a really hot day, we could only load some products at night when it was cooler.

“Here, we don’t have any theft or loading problems,” he said on a recent rainy afternoon when route drivers in their shirt sleeves were loading their trucks — dry and warm at some of Canteen’s 16 underground docks.

Temperature and humidity control also are draws for furniture maker Ian Byrne and a dozen employees in Byrne Custom Woodworking’s 30,000-square-foot space. There’s comfortable room to build the hand-crafted furniture, custom cabinets and plantation shutters that are the company’s signature products.

“The humidity control is great. Our raw wood never goes bad sitting around,” Byrne said. “It’s just a fascinating, comfortable woodworking environment.”

With one exception: When he found it would cost more than $100,000 to cut a special 65-foot ventilation shaft to do painting or varnishing in the underground, he kept the finishing part of his business in the West Bottoms, where his entire business previously was located.

Byrne, who also is lead singer for the Celtic rock band The Elders, and his wife, television reporter Kathy Quinn, who also works in the furniture business, said they’re sold on the underground location.

“I’ve only had one designer who came down here once and said he was claustrophobic and he couldn’t come back again,” Byrne said. “So I just meet with him up above.”

To reach Diane Stafford, call 816-234-4359 or send email to stafford@kcstar.com.