Promising British sprinter Harry Aikines-Aryeetey has severed his ties with controversial coach Trevor Graham.
Aikines-Aryeetey is the world youth champion at 100m and 200m
The US Olympic Committee has banned Graham because several athletes he has coached, including Justin Gatlin, have tested positive for banned substances.
World youth champion at 100m and 200m, Aikines-Aryeetey trained with Gatlin and Graham for 10 days in April.
"It's not an environment we want Harry to be a part of," the 17-year-old's coach Matt Favier told The Times.
"Until the investigations are over there are too many reasons why we shouldn't continue the relationship."
Olympic 100m champion Gatlin revealed last week he had tested positive for testosterone, the second time in his career that he has failed a drugs test.
His case is expected to be heard by the United States Anti-Doping Agency hearing next Monday.
After returning from the North Carolina training camp with Gatlin and Graham, Aikines-Aryeetey said his sprinting had improved.
He was offered the chance of training full-time in America by Graham but turned down the opportunity.
Aikines-Aryeetey became the first sprinter in the history of the World Youth Championships to land the 100m-200m double in Morocco last year.