A construction worker in Arlington was killed Monday afternoon after being hit by a piece of equipment, officials said.

An excavator being used at a construction site at Fourth Street and George Mason Drive tipped over and killed a man believed to be the operator, Capt. Tiffanye Wesley of the Arlington County Fire Department said. The accident occurred about 3:30 in the afternoon; the man was dead by the time firefighters arrived at the scene.

Arlington police and a medical examiner were on the scene investigating the cause of the accident and awaiting staff from the Occupational Safety and Health Administration. The worker was not publicly identified.

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