WALTHAM (CBS) – A manhole cover lifted off a Waltham road and hit a car Wednesday, injuring the driver. It happened on Wyman Street in the early afternoon.

Eversource crews reset the 200-pound manhole cover with relative ease, but the car it tore into told of a violent impact.

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Kirk Murphy, of Douglas, was driving his Prius when some sort of underground blast sent the metal disk flying.

A car was hit by a manhole cover in Waltham (WBZ-TV)

His wife said he doesn’t remember much about the incident itself, as he was knocked unconscious until a passerby helped pull him to safety through the passenger side door.

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His wife said Murphy was woozy and in a lot of pain as doctors at Lahey Hospital in Burlington ran CAT scans and MRIs.

Eversource blames the incident on “equipment failure” but explosions of underground transformers or pockets of natural gas have sent manhole covers airborne in the past.

Murphy’s driver’s side door and roof absorbed most of the impact. Had it come through the windshield, this might well have been deadly.

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Murphy’s wife tells WBZ he wants authorities to pinpoint exactly what happened so there won’t be any repeats.