Members of the United States swim team at the Tokyo Olympics have been alerted of alleged positive drug tests among the Chinese team that could impact the outcomes of multiple races as well as change the medal distribution of certain events at the Games, according to Pat Forde.

China’s top female swimmer Zhang Yufei tested positive for a banned substance prior to the Olympics, and went on to swim anyway, according to a report from The New York Times. Yufei won four medals at the Olympic Games, including two gold medals. Her gold medal in the women’s 200 m butterfly set an Olympic record, and she helped set a world record in the women’s 4 x 200 m freestyle relay.

China also had two male swimmers test positive for a banned substance before the Toyko Games, but both were cleared by China and the World Anti-Doping Agency to compete. Shun Wang won gold in the 200 m individual medley. Qin Haiyang also tested positive, but did not medal in the Games. He did, however, become the world-record holder in the 200 m breaststroke in 2023.

German television station ARD, which shared reporting on the doping story with The New York Times, indicated that in total, 23 top Chinese swimmers tested positive in 2021 but were secretly cleared for the Games. The banned substance that the 23 athletes tested positive for was trimetazidine, which is a medication used to treat heart-related conditions like angina. The drug aids in the metabolization of fatty acids, which helps the body use oxygen and allows for more blood flow to the heart, per WebMD.

As of Saturday morning, USA Swimming and the U.S. Anti-Doping Agency have yet to comment on any sort of investigation or reallocation of Olympic medals.

China won six medals in swimming during the Tokyo Games, which were contested in 2021 following a year-long postponement due to the COVID-19 pandemic.

This is a developing story and will be updated.