In letter, USADA says it can't change marijuana rules alone

Sha'Carri Richardson waves after winning the women's 100-meter run at the U.S. Olympic Track and Field Trials Saturday, June 19, 2021, in Eugene, Ore. (AP Photo/Ashley Landis)

In this June 19, 2021 photo, Sha'Carri Richardson celebrates after winning the first heat of the semis finals in women's 100-meter runat the U.S. Olympic Track and Field Trials in Eugene, Ore. Richardson cannot run in the Olympic 100-meter race after testing positive for a chemical found in marijuana. Richardson, who won the 100 at Olympic trials in 10.86 seconds on June 19, told of her ban Friday, July 2 on the “Today Show.”(AP Photo/Ashley Landis)