l am trying to convince my parents to let me get into the sport of drifting.l have the car but l need to convince them that it is a safe and harmless sport.Has anybody ever died or been seriously injured in a drifting accident?I've seen crashes but no injuries.

Any form of motorsport has it is risks. But then again u could be hit by a bus walking down the street minding ur own business.
Seriously tho, I'd rather u did ur stuff on the racetrack where the risk is only to yourself & not someone minding their own business on a public street. Sanctioned events here in Australia must comply with stringent safety standards regarding medical facilities, car scrutineering etc. before being allowed to proceed.
As to ur question of deaths in drifting, none that l am aware of. Seen a few trashed cars tho.

l am sure some where it has happened but then again drifting is not really a sport just stunts some kids saw in a movie. And l am sure it cost a lot of money and it can all be gone in a second.

well l guess people have died when they r competing in normal rallys & races & they have drifted side ways into barriers, trees etc.
Eg Peter Brock (not sure where u r askin from) in Australia died when his car drifted side ways off a rally stage & hit a tree.
Like any motorsport of course there r risks, u may not die but u could end up with serious injuries that could prevent u from participating further. personally l love driftin round in my own yard but i'm not sure i'd want to compete & take it further.

There is no such thing named harmless sport! You can suffer injuries playing tennis! Yes like any other sport there were many serious injuries that cost a limb sometimes, yet most of them were illegal but one or two of them were legal but l have not seen any death cases