Haunted Mine Drop, Glenwood Caverns Adventure Park

A 6-year-old girl fell 110 feet (33.5 m)  to her death on the Soaring Eagle underground drop ride. It was later determined that her seat belt was fastened under, rather than over her lap. Source

Superflip 360, Funland, Rehoboth Beach, Delaware, USA

Two girls, 14 and 15 years old, and one 16-year-old boy were injured by flying metal when a compressed air-tank near the Chinese manufactured inverting pendulum ride exploded. All three were taken to hospital, the male with a serious head injury. Source