The death of British actress Natasha Richardson from a severe brain injury following a skiing accident has reignited the debate over helmets on ski slopes. Richardson, 45, a member of Britain's Redgrave acting dynasty, fell during a private skiing lesson on a beginners' slope at Canada's Mont Tremblant resort on Monday. She died in New York on Wednesday, surrounded by her family. Her death came about 10 years after singer-turned-politician Sonny Bono and Michael L. Kennedy, son of assassinated Robert F. Kennedy, died after skiing into trees at high speed and not wearing a helmet. Richardson was reportedly not wearing a helmet. Helmets, once rarely seen on skiers or snowboarders, have become increasingly popular but the jury remains divided on their effectiveness and whether their use should be compulsory. Some medical groups claim that 60 percent of head traumas could be avoided, and some countries are also introducing laws over helmet use for children. Jeff Hanle, a spokesman for the Aspen Skiing company that runs resorts in Colorado, said all children under 12 at Aspen ski schools had to wear helmets but otherwise it was not mandatory. Some skiers and snowboarders resist wearing helmets, complaining they are too hot or muffle sounds, while some fear it encourages risky behaviour by giving a false sense of security. Sales of helmets in Germany have doubled since a skiing accident in the Austrian resort of Styria in January which left one woman dead and German politician Dieter Althaus seriously injured, his life believed to be saved as he wore a helmet. The Australian Ski Areas Association supports wearing helmets but says the decision is a personal or parental choice.