Gay wouldn't reveal the substance in a phone conversation from Amsterdam on Sunday, but he said he was notified by the U.S. Anti-Doping Agency late last week that a sample came back positive from a May 16 out-of-competition test. He said he will have his "B'' sample tested soon, possibly as early as this week.
"I don't have a sabotage story. I don't have any lies. I don't have anything to say to make this seem like it was a mistake or it was on USADA's hands, someone playing games," said Gay, who fought back sobs as he spoke. "I don't have any of those stories. I basically put my trust in someone and I was let down."
Asked who that person was, Gay replied: "I can't really say it. Sometimes a human being naturally, generally trusts somebody. That's what people do."
A triple world champion in 2007, Gay was healthy again this season after being constantly plagued by hamstring and groin ailments, along with a surgically repaired hip. He won the 100 and 200 at nationals last month, setting up an anticipated showdown with Usain Bolt at worlds.
But that's been scrubbed. Gay also said he will pull out of a meet in Monaco and fly back to the headquarters of USADA in Colorado Springs, Colo., to be on hand when his "B'' sample is tested.
A few years ago, Gay was part of USADA's program called "My Victory," where athletes pledge to compete clean. In his testimonial on the website, Gay said, "I compete clean because I really believe in fairness, and besides that, my mom would kill me! Just being honest."
He's spoken with his teammates, friends and family, including his mother and daughter.
"They already know it is some type of accident, or some type of - I don't want to use certain words, to make it seem like an accident, because I know exactly what went on, but I can't discuss it right now," he said. "My career and my name have always been better than medals or records or anything like that. I've always wanted a clean name with anything. Unfortunately, I have to break this news, that I have a positive 'A' sample."
In a statement, USATF CEO Max Siegel said: "It is not the news anyone wanted to hear, at any time, about any athlete."
Siegel added: "We do not know the facts of this case and look to USADA to adjudicate it and handle it appropriately."
Gay wouldn't go into specifics about the case, saying he couldn't "discuss it" when asked if what he tested positive for was a steroid.
"I have to go over everything with USADA first," said Gay, who finished fourth at the London Games last summer. "I will take whatever punishment I get like a man. I do realize and respect what I put in my body and it is my responsibility.
"I'm going to be honest with USADA, about everything, everybody I've been with, every supplement I've ever taken, every company I've ever dealt with, everything."