Four-time Tour de France winner Chris Froome failed a drugs test during the Vuelta e Espana race in September, cycling’s governing body UCI said on Wednesday. The British Team Sky rider had twice the permitted level of legal asthma drug Salbutamol in his body during the race in September, according to a joint investigation by The Guardian and Le Monde.

The cyclist’s lawyers and scientists are working on challenging the drug test result but if he is not able to provide a suitable explanation, he will have to forfeit his title. Froome also faces the possibility of being banned for a significant amount of time, according to The Guardian, which may rule him out of the Giro D’Italia and the Tour de France next year.

However, the cyclist denied any wrongdoing and said he was aware of the rules. “It is well known that I have asthma and I know exactly what the rules are,” he said, according to a statement released by Team Sky. “My asthma got worse at the Vuelta so I followed the team doctor’s advice to increase my Salbutamol dosage. As always, I took the greatest care to ensure that I did not use more than the permissible dose.”

Froome added that the UCI is “absolutely right” to examine test results and assured that his team will provide whatever information is needed.

If the charges hold, Froome won’t be the first cyclist to be banned for excessive intake of salbutamol. In 2007, Italian cyclist Alessandro Petacchi was handed a 12-month ban for the same, along with having to forfeit his five stage victories at the Giro D’Italia.

With inputs from AFP