How sanctions work

Contamination and no fault cases

An athlete who proves how a substance got into their body, and that they were not at fault or not significantly at fault, can have a ban eliminated or reduced. Proving the source is usually the hardest step.

• USADA said that in contamination cases the source must be proven and must match the level found in the sample.¹
• No Fault or Negligence eliminates the ban. Ysaora Thibus was cleared after CAS accepted contamination through kissing a partner who was taking ostarine.²
• No Significant Fault or Negligence reduces the ban. Iga Swiatek received one month after the ITIA accepted contamination of a melatonin product.³
• Proving a source but still being at fault leads to a reduced ban. CAS found Paul Pogba took DHEA by mistake in a supplement but should have taken greater care, and set 18 months.⁴
• Contamination claims often fail on the evidence. CAS rejected Erriyon Knighton's contaminated oxtail explanation and Tara Moore's contaminated meat explanation, imposing four years in each case.^5,6
• WADA's summary of the 2027 Code says the definition of a contaminated source is broadened to cover food, drink, the environment and contact with another person.⁷

Sources

1. USADA, Statement from USADA CEO Travis T. Tygart on contamination cases and the requirement of transparency (30 July 2024)
2. Court of Arbitration for Sport, CAS dismisses WADA appeal in the case of Ysaora Thibus (France) (7 July 2025)
3. International Tennis Integrity Agency, Polish tennis player Iga Swiatek accepts one month suspension under Tennis Anti-Doping Programme (28 November 2024)
4. Court of Arbitration for Sport, CAS confirms the ADRV committed by Paul Pogba but reduces the period of ineligibility from 4 years to 18 months (7 October 2024)
5. Court of Arbitration for Sport, CAS upholds appeals by World Athletics and WADA to impose 4 year ban on sprinter Erriyon Knighton (USA) (12 September 2025)
6. Court of Arbitration for Sport, CAS upholds appeal by ITIA against Tara Moore (15 July 2025)
7. WADA, Summary of major changes, 2027 World Anti-Doping Code (13 February 2026)