A 32-year-old woman died after a falling from the 15-year-old Russian-made Wild Mouse coaster. 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…
Mountain Coaster, Wisp Resort, Maryland, USA
A 56-year-old man died after being ejected from the alpine coaster sled into an embankment for unknown reasons. Investigators said the coaster ride and seat belts were determined to be in working order.
Zipline, Jungle Surfing, Queensland, Australia
A 50-year-old man died and his 48-year-old wife was seriously hurt in the Daintree Rainforest when their zip line cable snapped and they fell more than 52 feet (16m) to the ground. The woman was hospitalized with suspected spinal, pelvic, shoulder and arm injuries. Source
Crazy Mouse, Winter Wonderland, Stoke-on-Trent, UK
A 21-year-old man suffered a broken pelvis and two broken wrists after falling 40 feet (12m) from a portable roller coaster he was assembling. Source
Star Flyer, Firminy Fair, Loire, France
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
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