This photo provided by the Box Elder County Sheriff's Office...

This photo provided by the Box Elder County Sheriff's Office shows the wreckage from an explosion at Northrop Grumman's remote rocket testing site on Wednesday, April 16, 2025, in Promontory, Utah. Credit: AP

PROMONTORY, Utah — An explosion at Northrop Grumman’s remote rocket testing site in northern Utah destroyed a building Wednesday.

Officers found no injuries or fatalities in their initial investigation of the wreckage, according to the Box Elder County Sheriff's Office.

Emergency crews had responded to reports of a loud blast and a dark plume of smoke rising over the rangelands at 7:38 a.m.

It was not immediately clear which building was destroyed and what its purpose was. The aerospace and defense company maintains a large presence in Utah, where it manufactures and tests solid rocket motors.

Northrop Grumman did not immediately release a statement.

The public is advised to avoid the area as officials continue to investigate.

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