Rosy Esparza fell to her death Friday evening at Six Flags Over Texas in Arlington. Witnesses say that Esparza had told an employee that her lap bar felt loose, and that she tumbled off of the Texas Giant roller coaster on its first drop.

The Texas Giant is the tallest steel-hybrid roller coaster in the world, taking riders 14 stories high. The original ride was made of wood, but was rebuilt two years ago to add steel tracks. It still has the original wood supports, but the steel tracks make for a smoother ride and can endure steeper drops and banks than the original structure could. The rebuild also included a new control system.

Witnesses say that Esparza fell off of the ride when it plummeted from a high peak. She was riding next to her son, one of two children who were with her at the park. Six Flags will do an investigation of the accident since safety standards are not regulated by the government.

There have been four other injuries on the ride this year, many of them related to whip-lash. The amusement park remains open, but they have closed the Texas Giant.