A 24-year-old mother of two died and her 20-year-old friend was hospitalized with traumatic brain injury after the women were ejected from their two-person chair approximately 33 feet (10m) to the ground. Source
Accidents
Theme parks and roller coasters are statistically very, very, very safe. Out of the millions of people who ride the thousands of rides every year, there are only a small handful of incidents. You are statistically more likely to be involved in an accident driving to an amusement park than having one at a park. The rarity of accidents is one reason why the media report them, similar to plane crashes.
Every important element of a ride is inspected on a regular basis and every ride is tested every day without passengers before it opens. A ride might not open, or a safety system might activate, if there is an imperfection. For theme parks to operate, they must obtain insurance and one stipulation is their rides are frequently inspected and signed off by a strict Health & Safety governing body. Every theme park does what they can to prevent accidents because the negative press would be bad for business.
Having said all that, theme park accidents still happen…
Xtreme, Deerfield Township, New Jersey, USA
A 10-year-old girl died after she was was ejected out of her lap-bar secured seat from a Wisdom Rides Scrambler type ride at the Deerfield Township Harvest Festival. Source
AirMaxx360, Kingston upon Hull, Humberside, England, UK
A 21-year-old woman was ejected approximately 32 feet (10m) from her seat on the AirMaxx360 spinning ride at Hull Fair. She was hospitalized suffering a broken jaw, broken ribs, neck and abdomen wounds, after landing on a neighboring Sizzler ride. Source
Balloon Ride, Yantai, Shandong Province, China
A 31-year-old mother and her three-year-old son fell to their deaths when the large helium balloon they were in slipped its moorings and floated away before plunging back to earth after it ruptured high in the atmosphere. Source
Playball, Potsdam, Brandenburg, Germany
A 29-year old ride attendant was hit and killed by the ride she was working on at the Potsdamer Volksfest. The Huss manufactured flipper ride unexpectedly started moving, slinging the woman from the moving deck off the side of the platform into a railing. Source (in German)
Quimera, La Feria Chapultepec, Mexico City, Mexico
Two men, aged 18 and 21, died when the wheel assembly of the last car came apart on the Schwarzkopf triple loop coaster, causing the car to fishtail and derail. At least two women were also injured. Eyewitnesses reported seeing a rider thrown from the car and other riders hit their heads as the flailing car was dragged around the track. Source
Deca Dance, Wijchen, Gelderland, Netherlands
Seven people were injured when a cart broke off the Breakdance ride at the Wijchen Kermis (fair). A 38-year-man and his son riding in the cart suffered the most serious injuries. The boy was ejected with a broken wrist, while his father ended up under the deck with multiple fractures to both legs and a head injury. The father’s right leg had to be amputated. Source (in Dutch)
Extreme, Brixton, London, England, UK
A 12-year-old boy broke both legs after falling from the high speed Remix thrill ride at Benson’s funfair in Brockwell Park. Source
Monorail, Movieland Park, Lago di Garda, Veneto, Italy
Seven people, including two children, were injured when part of overhead monorail track and two carriages fell approximately 7 feet (2m) to the ground. Source
Twister, Lightwater Valley, Ripon, North Yorkshire, England, UK
A six-year-boy was airlifted to hospital with non-life threatening injuries after falling 30 feet (9m) from the Twister roller coaster. Source (w/video)