Building Explodes at Northrop Grumman’s Utah Plant for New Nuclear Missile

An explosion destroyed a building at Northrop Grumman’s Promontory missile and rocket plant in Utah’s West Desert on Wednesday morning, according to a press release from the Box Elder County Sheriff’s Office and an email sent to Northrop Grumman employees.

The email, shared with Inkstick, said that there was an “explosive incident” at the Promontory North Plant on Wednesday morning, which the Sheriff’s office said occurred at 7:38am. The email to employees said that all employees were safe and accounted for. A photo from the Sheriff's office showed an incinerated building with bare beams exposed and plumes of smoke and flames still visible in the hilly West Desert area. A fire in the area burned for at least an hour and a half.

Eric Olsen, the communications director for the Utah Labor Commission, told Inkstick that Utah’s Occupational Safety and Health division was aware of the incident but was not investigating since there were no reports of injuries. Box Elder County Sheriff Cade Palmer told Inkstick that Northrop Grumman was “managing the incident” and that inquiries should be directed to their media representative. Spokespeople for Northrop Grumman did not respond to phone calls and emails from Inkstick.

The six mile-long plant, which was originally constructed in 1957, is closely watched by nuclear weapons observers since it is the final assembly plant for the new Sentinel intercontinental ballistic missile. Once manufactured, the Air Force intends to load hundreds of those ICBMs with warheads and drop them into silos across the American West, where they will be on continuous alert for launch orders to shoot over the North Pole and reach Russia or China in about 30 minutes. Northrop Grumman did not respond to questions about which programs may be affected by the building’s destruction. The plant works on systems in addition to the Sentinel ICBM, such as rockets for NASA and the Space Force. A spokesman for Hill Air Force Base, which oversees the nuclear missile produced at the plant, did not respond to a phone call and email from Inkstick.

The future of the Sentinel program may be in doubt. The Air Force in February officially stopped work on designing new silos for the ICBM and announced that it was preparing to life-extend the existing Minuteman III missile until 2050. In 2020, the Pentagon estimated that the Sentinel missile would cost $78 billion; just four years later, the cost estimate had jumped 81%, to $141 billion. The Trump administration recently named Sentinel among a list of weapons programs to be “scrutinized” for potential cancellation.

History of workplace deaths and accidents across Utah

The explosion is the latest incident in a history of workplace accidents at Northrop Grumman properties across Utah.

In 2023, two employees, Jonathan Steinke and Ken Tran, died due to argon gas asphyxiation at a plant in Magna that also is part of the Sentinel ICBM supply chain, according to an economic development contract obtained by Inkstick that lists the addresses of Utah facilities contributing to the new ICBM. After Northrop Grumman declined to name the men publicly or detail the circumstances of their deaths, Inkstick reported their identities and cause of deaths in an exposé after an eight-month investigation.

Read more: Dying to Make Hypersonic Missiles in Utah

Utah Quietly Downgrades Northrop Grumman Worker Death Charges

At another plant that is part of the Sentinel supply chain, in Clearfield, Utah, three employees suffered foot injuries, including broken bones, when a metal lid weighing 6,750 pounds fell onto their feet last September, according to an incident report obtained by Inkstick through a Government Records Access and Management Act (GRAMA) request. Olsen, the Utah Labor Commission spokesman, told Inkstick that UOSH did not send on-site investigators to that location because “preliminary discussions” with Northrop Grumman indicated “the likelihood of no violations of workplace safety standards in these specific cases.”

Before it was acquired by Northrop Grumman in 2018, the Promontory plant where the explosion occurred Wednesday was the site of two mass workplace fatalities during the Cold War. According to Washington Post reporting at the time, five workers were killed in an explosion in 1987 that occurred after 100,000 pounds of solid-rocket fuel had been placed inside an ICBM known as the MX missile. In 1963, three people were killed at the plant due to a fire during missile production. And in 1967, one employee was killed by poisonous fumes at the plant.

The incidents underscore the hazardous nature of missile and rocket manufacturing.

An internal safety training slide for Northrop Grumman, sent by an employee to Inkstick, says that 104 fatal injuries have occurred at Northrop Grumman’s propulsion systems properties since 1960. Those worker deaths included ones at companies Northrop Grumman acquired such as Hercules, which formerly operated the Magna plant, and Thiokol, a chemical company whose search for “cheap, unproductive land” where it could conduct “explosive” operations in the early years of the Cold War led it to Promontory and are part of the origin story of the nuclear weapons industry in Utah.

There’s a lot of questions we still have — what caused the explosion? Were any workers nearby? What programs did the facility contribute to? We’ll be submitting public records requests in the coming weeks to dig into this incident, just as we’ve done with past accidents and fatalities at Northrop Grumman — stay tuned.

And if you have tips: [email protected], or send me a Signal message at tkbarnes.10

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