Michael O’Clair, 21, of Shirley, died at the scene after the snowmobile he was driving along the right-of-way for overhead power lines between Mount Henry and Leominster roads went off a sharp embankment, crashed into tree limbs and fell 40 feet.

His passenger, Jennifer Testa, 26, of Pepperell, was listed in critical condition yesterday at UMass Memorial Medical Center in Worcester.

A Leone spokeswoman, declined to discuss details.

Police found a helmet near Testa, but did not find one for O’Clair at the crash scene. State law requires that snowmobile riders wear helmets.