Nearly a dozen people reported being injured in the last five years while riding the Six Flags Over Texas roller coaster from which a woman fell to her death last week, though the most serious injuries appear to be a concussion and muscles strains due to jostling, state records show.
Six Flags Over Texas reported 14 injuries involving the Texas Giant roller coaster between April 2008 and April 2013, according to Texas Department of Insurance records. Three of those injuries happened either before or after the ride, such as tripping on the steps leading to the roller coaster.
It wasn't immediately clear how many of those injuries prompted the ride to be shut down, department spokesman Jerry Hagins said. If an injury requires medical attention and involved the actual ride, the ride must be closed until it gets a new safety inspection, he said.
"Our role is to make sure that happens," Hagins said, adding that the Texas Giant was currently closed and wouldn't reopen until the department sees a new safety inspection report.
Amusement park safety analyst Ken Martin noted that such injuries are self-reported, so it's hard to gauge their accuracy. He also said such numbers don't include "near-misses."
"The numbers that we hear about are typically the tip of the iceberg," he said.
Walter Reiss, an amusement park ride safety inspector, added that fatal accidents on roller coasters "are very unusual and infrequent."
"Most times that you have death accidents, it was something either ignorant or human error," he said.
The investigation is ongoing into how Rosa Ayala-Goana fell while riding the roller coaster Friday evening at the Six Flags amusement park in Arlington. A witness told local media that Ayala-Goana expressed concern moments before the 14-story ride began that the safety bar had not completely engaged.
The Tarrant County medical examiner's office confirmed Monday that the 52-year-old Dallas resident was the victim in the accident, and that she sustained "multiple traumatic injuries" during the fall.
A man who identified himself as Ayala-Goana's son declined comment Monday when approached at her home.
Six Flags Entertainment Corp. President and CEO Jim Reid-Anderson said Monday that company was using "both internal and external experts" to investigate the accident, but he offered no details during a conference call to discuss the company's earnings.
"Friday's accident remains under investigation by both company and external experts," Six Flags spokeswoman Sharon Parker said. "Until complete, we will not comment or speculate on what happened. Our thoughts and prayers remain with the family."
Arlington police and the Tarrant County District Attorney's Office are not involved in the investigation.
A dozen Arlington police officers responded to the park after Friday's accident and conducted interviews and a death investigation. Under Texas state law, police must look for criminal negligence and signs of whether or not the operator of the ride was intoxicated, Arlington police said.
The district attorney's office said it only gets involved when a criminal case is brought to it or if an arrest is made.
Meanwhile, Six Flags has temporarily closed the Iron Rattler roller coaster at its Six Flags Fiesta Texas in San Antonio. The decision came late Friday after officials heard about the accident in Arlington, Fiesta Texas spokeswoman Sydne Purvis said Monday.
Purvis said it's a precautionary move until the Texas Giant investigation is completed. Both roller coasters are wooden structures with steel rails.
The Texas Giant first opened in 1990 as an all-wooden coaster but underwent a $10 million renovation in 2010 to install steel-hybrid rails before reopening in 2011. The coaster, which can carry as many as 24 riders, has a drop of 79 degrees and a bank of 95 degrees.
Reiss, the amusement park expert, speculated that either Ayala-Goana managed to slip out from behind a locked mechanism or that the harness mechanism failed and it opened.
"Right now, I would say investigators are probably tearing apart every inch of that train and every harness mechanism, and inspecting and testing every millimeter of those harness mechanisms to find out whether the potential even exists for her harness to have failed or for any other harness to have failed," Reiss said.
"At the end of the day, it comes down to whether or not the person fits," he added. "If the harness locks normally, without forcing it, it's OK. And the final say is up to the ride operator to tell you, 'I'm sorry, you can't ride."'
The roller coaster was issued its most recent safety permit in February and was in compliance with state regulations that require an annual inspection by a qualified engineer, according to state records. Proof of those inspections also must be submitted to the Texas Department of Insurance.
Hagins noted that Texas has an insurance-based regulatory system for amusement park rides and that the ride also was in compliance with rules that require $1 million liability insurance.
Ken Martin has called for more oversight, as Texas does not have agency to oversee accidents or deaths at amusement parks.
"We need people who are specially trained in amusement ride and devices to conduct investigations," he said.
The Dallas Morning News has reported that officials with the roller coaster's car manufacturer, Gerstlauer Amusement Rides in Germany, were set to come to Texas to inspect the ride. The company could not be reached late Monday by phone and an email was not immediately returned.
Don Hankins, of Lakeland, Fla.-based PLH & Associates, Inc., who inspected the roller coaster in February, did not return a call to The Associated Press on Monday.
Massachusetts Senator Calls for Better Oversight for Roller Coasters
U.S. Sen. Edward Markey is calling for a set of national safety standards to cover rides at amusement parks following Ayala-Goana's death.
Markey said families on summer vacations are assuming what he called a huge risk because of the lack of federal regulations.
The industry has argued that accidents, particularly fatal accidents, are rare at amusements parks.
Markey, however, said there are enough serious accidents to warrant federal intervention.
The Massachusetts Democrat said regulations should cover what he called the "totality of the safety system" for roller coasters and other rides.
He said families who visit amusement parks in other states should be confident that all rides meet the same federal standards.
NBC 5's Ray Villeda and Associated Press writers Uriel J. Garcia and Nomaan Merchant contributed to this report.