The mission and history of Loring Air Force Base in Limestone are well known in Maine, but until recently, few people were aware of a top-secret installation next door to the Strategic Air Command base that closed in 1994.

On Oct. 10, a school bus full of sightseers rolled through a once tightly secured gate carrying its passengers back into the Cold War era when, as one of them recalled, “Those of us who grew up in Presque Isle spent a lot of time under our desks.”

The group was entering an area east of the base that, in 1952, became the nation’s first operational nuclear weapons storage site, according to the book “North River Depot” by John C. Garbinski, who served with the 42nd Bombardment Wing at Loring in the 1980s.

“I have only gotten used to talking about it in the past 10 years,” said David King of Limestone, as he narrated the tour.

When King was a member of the security police squadron at Loring in the 1960s, he was limited to one official response to questions about the area. He could “neither confirm nor deny” that it contained nuclear weapons.

The 400-acre site is now part of the Aroostook National Wildlife Refuge maintained by the U.S. Fish and Wildlife Service, and Betty Rinehart of Caribou, president of the Friends of Aroostook National Wildlife Refuge, joined King in narrating the tour.

“I represent the past,” he said, “and Betty can tell you about the present and the future.”

As the bus traveled from the Aroostook National Wildlife Refuge visitors center toward the storage area, Rinehart said they were on a road that traversed a nesting area for the upland sandpiper. The Friends group arranged for construction of a new route to the weapons area, so the sandpipers can nest in peace.

Such projects support the Friends’ goal of restoring the ecological diversity of the area. As a pleasing bonus, when workers tore up an abandoned parking lot to acquire materials for the new road, they discovered a wetland underneath, so another feature of the landscape also is recovering.

The bus rolled slowly past the first of two gates at the entrance to what was the high-security section of the site.

“We called this the ‘Sally port,’” King said, describing how a vehicle would be contained between two closed gates while guards at the gatehouse processed the individuals in the vehicle.

“You had to pass security to be given an exchange badge,” King said, recalling an elaborate system of badges used to establish positive identification for admission to the storage area.

According to Garbinski, the facility was the first of five similar storage sites across the country constructed between 1951 and 1953 “to provide operational storage of the nuclear stockpile and to provide a specific number of weapons to their adjacent SAC bases.”

Completed in 1952, it contained barracks, recreational facilities, warehouses, offices, weapon maintenance areas and a separate fenced-in area that included 27 storage igloos.

“The facility was originally composed of two ordnance storage areas, an assembly area and a base spares area, all of which were surrounded by a parallel series of four security fences,” Garbinski said in his book. Each fence was 8 feet high with six strands of barbed wire on two outriggers (three on each side). The third fence was electrified with enough voltage to subdue or even kill an intruder.

Known originally as “North River Depot,” it is said the site was designed to look like a village from the air. It was in fact, Garbinski said, “a maximum security storage area for the most advanced weapons of mankind.”

King said that the site was independent of Loring Air Force Base — a separate microcosm of the base — and “90-95 percent of the people stationed at Loring did not come out here.”

He said the weapons were transported by trailer to the flight line and then lifted into the aircraft.

“The haul road to the flight line used to be as smooth as a baby’s butt,” he said as the bus passed the now overgrown roadway. He said grass on the storage site was mown close to the ground to enable guards to see intruders, and at night, “the area was fully lit up like a baseball stadium.”

A passenger on the bus who also had worked at Loring recalled, “People on the flight line thought the lights were the town of Limestone.”

Another passenger voiced a common observation: “People lived here all their lives and never knew this was here.”

Garbinski offers a response in the introduction to his book: “Although the Cold War can be described as a war of ideology, the truth is that it was also a war of secrets. Secrets kept from the enemy; secrets kept from the American people as well.”

He dedicates his work to the “Silent Peacekeepers” — military personnel responsible for “secrets kept at the highest level of our military and of our government … secrets that had to be kept because they pertained to the most devastating weapons mankind had ever developed.”

Today, nature is reclaiming the now decontaminated North River Depot with help from the Friends of Aroostook National Wildlife Refuge — an effort called “From Bombs to Biodiversity.”

As the fences come down, diverse forms of wildlife are rediscovering the area, causing Rinehart to observe, “This was their territory before the military took over.”

For more information, visit facebook.com/Friends-of-Aroostook-National-Wildlife-Refuge-292184713369/.

Kathryn Olmstead is a former University of Maine associate dean and associate professor of journalism living in Aroostook County, where she publishes the quarterly magazine Echoes. Her column appears in this space every other Friday. She can be reached at kathryn.olmstead@umit.maine.edu or P.O. Box 626, Caribou, ME 04736.