China Rob Schumacher-USA TODAY Sports

Ahead of the Toyko Olympics, 23 different Chinese swimmers tested positive for a banned drug but were allowed to compete by the World Anti-Doping Agency.

According to Reuters, the World Anti-Doping Agency confirmed that the 23 swimmers tested positive for trimetazidine (TMZ), which is a banned substance found in heart medication. However, the WADA accepted China’s claim that the swimmers returned adverse analytical findings (AAFs) after inadvertently being exposed to the drug through contamination.

“WADA ultimately concluded that it was not in a position to disprove the possibility that contamination was the source of TMZ and it was compatible with the analytical data in the file,” WADA said in a statement. “WADA also concluded that … the athletes would be held to have no fault or negligence. As such, and based on the advice of external counsel, WADA considered an appeal was not warranted.”

China had a strong performance at the Tokyo Olympic Games, as the 30-member swimming team won six different medals at the Olympics, including three gold medals.

Reuters indicates that the news outlet requested comment from CHINADA, China’s anti-doping agency, as well as the Chinese Swimming Association. However, neither of the organizations responded to the request for comment immediately.

[Reuters]