Swimmers at the US Olympic Trials insist they are squeaky clean when it comes to doping but do not share the same confidence over the competition they could face in just over five weeks at the Rio Games.
With the Russian track and field team suspended from the Rio de Janeiro Games for systemic doping and a potentially similar sanction awaiting the country's weightlifters a cloud of suspicion lingers over all of the country's athletes.
World Anti-Doping Agency (WADA) chief Craig Reedie warned on Monday that they would call for "serious" action against Russia if a new investigation led by Canadian law professor Richard McLaren unearths more evidence of widespread state-sponsored doping.
"There is definitely a lot of talk, but, you know, I'm 100 per cent confident that the US Olympic Team will be 100 per cent clean; there is no doubt in my mind," said Elizabeth Beisel, who will be one of the busiest athletes at trials trying to qualify in nine events.
"It is sad that some athletes, no matter what sport you're in, are choosing to dope.
"It's always going to be in the back of your mind, thinking about it."
The drugs question is one that is certain to linger over the June 26 to July 3 US Trials as the Russian doping shadow creeps into the pools.
Some US swimmers qualifying for Rio face the prospect of going up against a Russian who has twice tested positive for a banned substance and could find herself competing at the Olympics in August instead of serving a lifetime ban.
Yulia Efimova, a four-times breaststroke world champion, tested positive for meldonium but has had a temporary suspension lifted pending a final ruling by the Court of Arbitration for Sport (CAS).
Hundreds of athletes this year have tested positive for meldonium but WADA has said their bans might be overturned due to a lack of clear scientific information on how long the drug takes to be excreted from the body.
If her ban is held up it would be the second offence for Efimova, who was disqualified for 16 months in 2014 by swimming's world governing body after traces of an anabolic steroid were found in her system.
