Jamaican sprinter and Olympic medalist Asafa Powell banned 18 months for doping

Asafa Powell has competed in the last three Summer Olympics. (Cameron Spencer/Getty Images)

Former 100 meter world record holder Asafa Powell has been banned 18 months for failing a drug test last year.

Powell, who has won three Olympic medals, called the sentencing "unfair and unjust," according to the BBC. From the BBC's report:

The Jamaican sprinter, 31, took the banned stimulant oxilofrine at last year's national championships but the suspension has been backdated and will end on 20 December, 2014.

Powell called the ruling "unfair and unjust", and said a legal supplement he took, Epiphany D1, was contaminated.

He plans to appeal to the Court of Arbitration for Sport.

The substance in question, oxilofrine, is banned by the World Anti-Doping Agency. Powell, who has competed at the last three Summer Olympics, was the biggest name in Jamaican sprinting before the rise of Usain Bolt.