Was that an explosion? Yes, but controlled at testing facility

Defense company Northrop Grumman calms concerns by discussing northern Anoka County proving grounds, regular detonation tests

by Ian Wreisner

APG of East Central Minnesota

Area Facebook groups have lit up in recent weeks with questions about possible explosions. Loud bangs and rattling have had people turn to their digital neighbors, none of which reported any explosions, fire or smoke in their neighborhoods. Some responses came from local police departments, with the answer having roots in Anoka County that go back 60 years: Northrop Grumman.

“This happens every year in the wintertime,” Northrop Grumman communications manager Jarrod Krull said. “It’s extremely cold, and the wind is blowing a certain direction, the ground is frozen, and basically what happens is when we’re testing munitions out there, it sounds louder. The shock waves travel further. And then there’s a spike in people wondering what’s going on.”

Krull, who has been with the company for 16 years, said that those Honeywell roots were laid in the state 60 years ago, with head offices under the Northrop Grumman merger now being stationed in Plymouth, Minnesota. Northrop Grumman works in the defense industry, with the St. Francis/Elk River site in question focusing on “medium and large caliber ammunition for fighting vehicles, tanks and ships.” The Anoka County site does not produce the ammunition, but is focused on “program development,” working as a testing site for the ammunition Northrop Grumman produces.

“Our proving grounds serve as a place where we can test things,” Krull said. “What we’re hearing right now, it’s a warhead test where we’re testing the functionality of the warhead. We call it energetic materials; in layman’s terms, it’s an explosive. That’s where people are hearing those booms. I think last week we had three days where we were doing about eight initiations, or explosions, a day.”

Krull shared that eight tests is a higher number for tests per day, but all the tests were “business as usual” for the site. The proving grounds occupy 3,200 acres of land for which there are ordinances in place with surrounding cities regarding noise. Northrop Grumman also follows a 9:30 a.m. to 4 p.m. regular testing schedule. Krull says that a combination of environmental factors is what has neighbors across the area hearing the tests more clearly than usual.

Cloud cover and lack of foliage on the trees in the proving grounds can also contribute to the sound and shock waves traveling further. Sound readings leaving the testing grounds are capped at 60 decibels, he said, and the readings from the days that generated the most calls came in at 40 decibels.

Paired with the busy testing days and more people moving to rural areas in the region, Krull says the volume for calls has increased. He also did not rule out the post-pandemic prevalence of remote work for those who would regularly be in an office now hearing the explosions during regular office hours.

“There’s so many factors, and I don’t want to make it sound like I’m downplaying it,” Krull said. “The work that we do there is like living next to a quarry where they’re blasting, or even if you’re living next to the airport and there’s some planes that come in louder than other planes. There are all these crazy factors; even with measures put into place, it doesn’t always not surprise people. Sometimes it seems louder than other times of the year.”

Social media comments checking in from Anoka, St. Francis, Coon Rapids, Andover, Otsego and Elk River all reported hearing or feeling the tests. Some wondered if chunks of ice that had recently hit their roofs came from the blasts, to which Krull replied there are no materials, debris or otherwise that make it off the proving grounds due to several safety systems in place.

Others also theorized that increased testing may be due to old ordnance being detonated. Krull confirmed that this sometimes happens with excess materials from government contracts, when it is decided it is better detonated than shipped back to the relevant contractor. He said that the content of tests is not specifically shared, however, due to security reasons.

“The short answer is that, for security purposes, we don’t let the public know what it is that we’re testing and when we’re testing it,” Krull said. “One thing is interference. Some of the things we work on are classified, so we don’t want to let classified information out. Sometimes for some of the different kinds of weapons that we store and safeguard up there, it’s just better for security that we don’t make it public in case there are bad actors out there who would potentially try to steal that equipment.”

Krull also said that it is understood among local agencies that testing will fall in that 9:30 a.m. to 4 p.m. window, and anything that falls significantly outside of that would be notified in advance to local government agencies.

With the increased number of calls in the past few weeks, Krull says that Northrop Grumman is considering how to better inform neighbors and agencies in the area. One way it’s already being done is with annual visits to the facility by first responders.

“Every year, we invite local firefighters and local responders out to the facility just to become familiar with where we store explosives and munitions,” Krull said. “In the event that there is a fire, some sort of mishap, local first responders will be familiar with the organization. They’ll understand what the setup is and what to expect when they come out to the scene.”

Krull said that the St. Francis/Elk River proving grounds have been a standard for safety in his time with the company, with no fire emergencies in its history and no Environmental Protection Agency violations in “many years.” He mentioned a thriving wildlife population of deer, turkeys and eagles on the property, as well as no contaminated water bodies nearby.

Krull also estimated that for the last 15 years in a row, the facility has received the Governor’s Safety Award given to the industrial sector.

“Those are things we’re very proud of,” Krull said. “We’re taking good care of the land out there, we’ve kept our people safe. The work that we do is sometimes noisy, but outside of that we haven’t had any fires, nothing gone off the proving grounds. We’ve had a really good safety record, but obviously the work we do is sometimes loud.”

Krull says that anyone who hears tests in the future and wants to confirm any concerns about potential explosions can call the proving grounds at 763-241-7530.