In the midst of World War II, the Lake City Army Ammunition Plant was a city in itself.

Furthermore, Michael Calvert said, its successful establishment and operation during that time helped Independence and surrounding cities eventually grow and even played a role in later manufacturing businesses putting down roots in the metro area.

Calvert, longtime area resident and a project manager for present-day Lake City operator Orbital ATK, gave the latest Lunch ’n’ Learn presentation Wednesday at the Truman Memorial Building, highlighting the early history of the plant in rural eastern Independence, which began operation 75 years ago, even before the United States had officially entered WWII. At its war-years peak, the plant – originally called Lake City Ordnance Plant, then renamed Lake City Arsenal in 1945 and given its current moniker during the Vietnam War years – employed more than 22,000 civilians, plus a couple hundred military personnel.

When Calvert asked the two dozen in attendance who among them worked at Lake City or had a family member who worked there, at least half raised their hands.

“Think about that,” Calvert said. “Where would you be? Would you even exist?”

Calvert's grandfather had a lumber delivery contract with Lake City, he said.

“If he didn't have that, my mother wouldn't have been here and met my father,” Calvert said.

Blue Springs, which in the 1940s had a tiny fraction of its current population, eastern Independence, Lee's Summit and even Buckner benefited from post-war settlement, Calvert said.

Roger Sermon, then the mayor of Independence, and then-Missouri Senator Harry Truman spearheaded the plant's establishment in December 1940, as the U.S. ballooned its defense budget and later started the Lend-Lease policy with Great Britain. Remington Arms operated the plant then, as it did until 1985.

When construction finished at that time, the plant had 340 buildings, 11 inner miles of railroad, 25 inner miles of road, parking for more than 4,000 employees, six cafeterias, a hospital and seven first aid stations on a campus of nearly 4,000 acres.

“That's a lot of people,” Calvert said.

Enough that the plant had its own recreational sports leagues – and plenty of opportunities for blood drives.

A 641-member police force kept things in line, with perimeter patrol done on horseback, and a fire department of 82 people stood at the ready.

The total price tag topped $51.3 million, “staggering amount” for that time, Calvert said. “It was the biggest thing in the industrial history of Jackson County.”

The first equipment arrived at Lake City on May 5, 1941, and production started on September 12. The plant produced and tested three different rounds of ammunition – .30 caliber, .50 caliber and .30 special. The first loads left via rail cars in November. By the end of the war, the Lake City had produced 5.5 billion rounds of ammunition.

“Some of that equipment is still there – we call it 'legacy equipment' – and is still working,” Calvert said.

More than half the workforce there were women, mirroring many other industrial places of the time. Calvert passed around a framed human resources badge from 1943 – donated to him by a man from Sedalia, whose grandmother left her hairdresser job in her mid-30s to work at Lake City.

Even with strong wages and regular raises, it wasn't easy to recruit workers, Calvert said – with 394 war-related plants in the immediate metro area and 332,000 employed in them. One percent of the total American war dollars was spent in a three-county area.

A one-time recruiting tool was a small production line set up for display in Municipal Auditorium. Lake City would send a truck around the area to drum up potential employees, Calvert said, and one recruiter liked to jump out of the truck, set up a .50 caliber machine gun and run through a belt of ammunition.

“That got people's attention,” he said. “Of course, they were all blanks.”

By December 1945, as the U.S. shifted back to peacetime, the workforce at Lake City plummeted to just 79 people. The plant was used as a depot and demilitarization spot for ammunition. When the U.S. entered the Korean War in 1950, the workforce jumped back to 15,000. Answering a question from the crowd, Calvert said the plant's history during Korea and Vietnam years could make for a future presentation.

“The mission has not changed in 75 years,” he said. “How many places can say that?”

He believes the success of Lake City, still the largest single producer of small arms ammunition for the armed forces and with NATO testing responsibilities, showed post-war industries that Independence and Jackson County could be a place to thrive.

“It was proven by this plant,” he said, “that the area has a large, stable, dedicated work force.”