The brain-injury death of Tony-winning actress Natasha Richardson, two days after a skiing accident, has rekindled debate over wearing helmets while skiing or snowboarding.

Ms. Richardson, 45, died Wednesday at Lenox Hill Hospital in Manhattan after falling at the Mont Tremblant resort in Quebec on Monday.

The accident caused an epidural hematoma, which involves bleeding between the skull and brain covering, said Ellen Borakove, a spokeswoman for the New York City medical examiner's office.

Some skiers, as with some motorcyclists, say helmets reduce enjoyment of "getting the wind in your hair," said Bryan Davis, snowboard supervisor at Seven Springs Mountain Resort in Champion, Pa.

An advocate of helmet usage, Mr. Davis said 20 to 30 percent of skiers at the resort wear helmets, and the percentage has been rising each year.

"It's an inherently dangerous sport," he said. "Most sports have dangers, some worse than others. But any time you get out of bed, you run the risk of injuring yourself more than you do by staying home under the covers."

Dick Barron, the resort's director of ski operations, also recommends helmets, but said people who wear them can have a false sense of invincibility.

Helmets, he said, help prevent injury when skiing at 14 mph, but are less protective at speeds that can reach 40 mph. For that reason, persons wearing helmets should ski as though they are not wearing one, he said.

Seven Springs, which straddles the Somerset and Fayette county line, has had four ski-slope deaths since opening in 1933, but those include deaths from heart attacks.

Adding to the debate is the fact Ms. Richardson was skiing on a beginner slope, where serious accidents are rare, Mr. Davis said.

Yves Coderre, director of operations at the emergency services company that sent paramedics to the resort where Ms. Richardson suffered her fall, told reporters that paramedics were told they were not needed and never saw Ms. Richardson.

Another ambulance was called later to her hotel, when her condition worsened, and she was rushed to a hospital.

"It sounds like she had a relatively prolonged period of being relatively OK," said Dr. Jack Wilberger, chairman of the Department of Neurosurgery at Allegheny General Hospital. "Usually with this type of problem people get into trouble in a short period of time.

"Such injuries involve a laceration of an artery just under the skull bone, which can lead to significant bleeding to build up to a level that causes unconsciousness," he said. "Usually unconsciousness occurs in 15 to 20 minutes."

Most hematomas occur in the region of the temple, where the bone is thin and doesn't take much trauma to cause a fracture, Dr. Wilberger said.

"It sounds to me that what happened to her is one-in-a-million kind of chance of occurrence," he said.

Dr. Mark Lovell, director of UPMC Sports Medicine Concussion Program, said the epidural hematoma apparently led to a rapid downturn.

"There's not much room between the brain and the skull, so when there is bleeding in the skull, there is nowhere for the blood to go," he said. "It basically pushes the brain out of the way."

Dr. Lovell, an expert skier and consultant to the U.S. Olympic snowboard and ski teams, said epidural hematomas account for only 1 to 2 percent of all brain injuries. Only 15 percent are fatal.

"There could be a pre-existing factor, such as an aneurysms, a weakness in an artery or malformation," he said. They usually are discovered accidentally, in CT scans for other conditions, he said.

Dr. Lovell said he always wears a helmet and recommends that adults and children on the slopes do so, as well. He said he knows of the hill at Mont Tremblant where the actor was injured. It's similar to beginner slopes at Seven Springs or Hidden Valley.

"We're not talking about any high-velocity injury," he said. "There was no huge insult to her head."

For people who have had a head injury and are unsure of its seriousness, Dr. Lovell advised:

"Anybody who has significant symptoms after -- headache, vomiting, loss of consciousness or amnesia or confusion -- those people should go to the emergency room and get it checked out."

The National Ski Areas Association, which released its Helmet Safety Fact sheet on Wednesday, said 43 percent of U.S. skiers and snowboarders wear helmets, which is up from 40 percent from the previous year and 25 percent in the 2002-03 season.

Seventy percent of children 9 years old or younger wear ski helmets, but only 12 percent of men 18 to 24 wear them, the association said.

More than half of all advanced skiers wear helmets, and more skiers overall wear them than the 20 to 25 percent of bicyclists who do. In the past 10 years, an average of 39 people per year have died from skiing -- fewer than swimming or bicycling.