Turkish weightlifter Sibel Özkan has been disqualified retroactively from the Beijing 2008 Olympics ©Getty Images

Turkish weightlifter Sibel Özkan has been disqualified retroactively from the Beijing 2008 Olympics and ordered to return the silver medal she won at the Games after re-analysis of her samples revealed banned substance stanozolol.

Ozkan, who placed second in the women’s 48 kilograms category, now faces the prospect of being banned by the International Weightlifting Federation (IWF). 

Bronze medallist Chen Wei-ling of Taiwan looks set to be upgraded to silver, while fourth-placed Im Jyoung-hwa of South Korea may get bronze.

The International Olympic Committee (IOC) revealed today that 30 athletes from Beijing 2008 and 15 from London 2012 have tested positive in the second wave of doping retests from the last two Summer Olympic Games.

A total of 23 medallists from Beijing 2008 produced provisional adverse analytical findings as a result of the second wave, which was predominantly focused on athletes who reached the podium in the Chinese capital.

As many as 1,243 doping samples from the Games have now been reanalysed, resulting in 98 positive tests.

Ozkan's reanalysis was carried out in the first wave, with both her A and B samples failing.

Weightlifting has proved to be a problem sport when it comes to doping with athletes from four countries - Azerbaijan, Belarus, Kazakhstan and Russia - to be banned from Rio 2016 in the event that it is proven they each produced three or more anti-doping rule violations in the combined re-analysis of samples from Beijing 2008 and London 2012. 

Bulgaria were excluded from Rio 2016 by the IWF Executive Board late last year because of 11 positive doping cases during the qualification period. 

Bronze medallist Chen Wei-ling of Taiwan looks set to be upgraded to silver ©Getty Images
Bronze medallist Chen Wei-ling of Taiwan looks set to be upgraded to silver ©Getty Images

The IOC announced the first results of retests from Beijing 2008 in May, where 31 athletes were found to have tested positive.

The organisation then found 23 positives from London 2012. 

It came after the IOC revealed it would extend its re-testing programme of doping samples submitted at Beijing 2008 and London 2012 to include all medal winners.

Earlier this week, Alexei Selyutin and Yekaterina Vlasova became the last Russian weightlifters to be banned for doping. 

Former European under-23 champion Selyutin was banned for four years and Russian national champion Vlasova for 18 months. 

The Russian Anti-Doping Agency hasn't provided details of the offences. 

The IOC are currently considering legal options over whether they could implement a blanket ban on the Russian team for Rio 2016.

They have faced calls to make the decision by the World Anti-Doping Agency and 14 National Anti-Doping Organisations.