BUFFALO GROVE, Ill. (CBS) — A worker fell into a subterranean vault in Buffalo Grove Wednesday, suffering a head injury that sent him to the hospital.

In the midday hours Wednesday, the man, who worked for the Northwest Water Commission, was working in a below-ground concrete vault filled with pipes, at Buffalo Grove Road and LaSalle Lane.

He fell off the steel ladder used to climb in and out of the vault, according to the Buffalo Grove Fire Department.

The worker fell about 15 to 20 inches and hit his head on some of the pipes in the vault.

He suffered a head injury and was taken to Advocate Condell Medical Center in Libertyville in stable condition, according to the fire department.

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