A Massachusetts subcontractor electrocuted Tuesday inside an AT&T building near Boston died from his injuries, authorities said.

Middlesex District Attorney Marian Ryan said in a release that authorities responded to the AT&T building in Cambridge at 8:30 a.m.

When they arrived they found a 44-year-old man in "need of immediate medical treatment."

CPR was performed and the worker was taken to Massachusetts General Hospital, where he was pronounced dead, police said. The worker’s name hasn’t been released.

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A preliminary investigation indicated that the man, a subcontractor, was working on an emergency lighting conduit when he was electrocuted, Ryan said.

Police said the power was shut off immediately and that the Occupational Safety and Health Administration (OSHA) is investigating the incident.

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AT&T did not immediately respond to Fox News Digital's request for comment.