Samantha Allen died about an hour after the ride ended.

Allen's death adds another name to a growing tally of individuals who have gotten on rides with no mechanical or safety errors, yet have somehow walked away with injuries. The trend has sparked efforts to increase oversight of such rides.

The cause of death for Allen was a tear to her aorta, according to autopsy reports -- a common complication for a person, such as Allen, with the connective tissue disorder known as Marfan syndrome.

Such tears can happen at any time to those with the genetic disorder, said Dr. Alan Braverman of the Washington University School of Medicine in St. Louis. But there is increased chance of tearing when the individual's heart rate or blood pressure increases, he said.

Braverman couldn't confirm whether the 2:20-minute ride -- at speeds nearing 50 mph with riders flying through the air with their face, chest and knees to the ground -- sent Allen's heart rate racing.

And Maryland state inspectors, who must certify such fixed-site roller coasters annually and re-examine them for mechanical or safety problems after accidents, ruled the roller coaster safe.

But some say a perfectly functioning ride might not necessarily be safe. With the explosion of more extreme coasters in the 1990s, some lawmakers want to know how much is too much.

Several new coasters boast top speeds of 100 mph and hold G-force ratings -- a measure of the amount of acceleration force exerted on a body -- at 6.5, more than the maximum 4 G's that astronauts feel while traveling up to 17,440 mph on liftoff, according to a 2002 article in the Annals of Emergency Medicine.

"It raises the question: Is there a problem here?" said David Moulton, a spokesman for Rep. Edward Markey, D-Mass., who is working on legislation to extend federal oversight beyond the traveling carnivals and fairs that the government now oversees.

"Riders of amusement park rides are not astronauts," Moulton said. "They don't go through the rigorous winnowing . . . to get down to the very few with the right stuff to ride the coaster," he said.

Instead, roller coasters are open to anyone of the right size, he said.

Markey became interested in the regulation -- what he terms the "roller coaster loophole" -- after a string of four amusement park fatalities nationwide during a six-day period in 1999, Moulton said.

Fixed-site parks, such as Six Flags, became exempt from federal oversight after the amusement industry successfully lobbied for exclusion in 1981.

The result is mixed regulation in most states and no government regulation of permanent amusement parks in states like Alabama, Mississippi, Kansas, Utah, Arizona, Montana, North Dakota and South Dakota.

Maryland lands on the higher side of oversight, requiring an annual state certification of rides at permanent parks and an inspection for traveling fairs each time a ride is moved. Rides also must be inspected after accidents.

"Maryland is consistently rated among the highest for amusement safety," said Gale Owens, a spokeswoman for the Maryland Division of Labor and Industry, the department that oversees amusement ride inspection.

Still, only New Jersey has contemplated posing limits on how extreme rides can be. And Moulton said the lack of standards worries Markey.

Some cases show that the whipping forces of roller coasters may cause bruising to the brain, Moulton said. And the rate of such injuries and the rate of increase in G-force limits are rising simultaneously, he said.

Markey's staff and the National Institutes of Health initially found 15 cases of people who have suffered such injuries since 1969. At first, the number "didn't seem that troublesome," Moulton said. Then they noticed that 14 of the 15 cases occurred since 1992.

The office has since found 60 cases of such injuries, and it plans to release the list on its Web site next week, he said. The staff continues to look for more.

Markey's office is also coordinating with the Brain Injury Association to form a panel to review medical literature and propose possible recommendations regarding ride regulation.

The panel is almost full and will include neurologists, amusement industry experts, engineers, and other professionals, said BIA spokeswoman Anne Rohall.

Besides limits and further study recommendations, the panel might also look at things like consumer warnings, Rohall said. Most roller coasters post signs to caution those with spine or heart conditions or those who are elderly or pregnant against getting on the ride.

"We know in the brain community it is dangerous to have an injury upon an injury," Rohall said. "Should there be warnings for those who have had a brain injury?"

Despite the investigations, amusement industry officials say their rides are safe.

"Safety is our No. 1 priority here at Six Flags of America (Largo)," said spokeswoman Karin Korpowski. All the park's rides are inspected daily, on top of periodic inspections by the state and outside consultants, she said.

"All of our rides are completely safe, or we wouldn't have them in our park," Korpowski said.

"Visiting a theme park today is far safer than bicycling, swimming, skiing, playing soccer, and dozens of other recreational activities," said Joel Cliff, spokesman for the International Association of Amusement Parks and Attractions, noting that nearly 320 million guests safely took more than 3 billion rides in 2001.

The statistics can favor either side.

Advocates of regulation point to a 1999 National Safety Council report that compared roller coaster accidents per mile ridden with other forms of transportation. The comparison found that coasters ranked second in number of fatalities, behind car crashes, but ahead of train, airplane and bus accidents.

Still, experts will look at the figures and release information as they conclude their analysis.

"This is not a witch hunt," Rohall said. The panel is going to look at the data and see what comes of it, she said.

And regarding Samantha Allen, "(Six Flags) is very saddened by this  unfortunate occurrence," Korpowski said. But "the ride is completely
safe," she said.

"Thousands rode it before and thousands have ridden it since," she
said.