CONCORD, N.C. -- NASCAR has added a list of banned substances for its drug testing policy to the 2010 rulebook that all teams have been provided, the body's vice president of racing operations said on Thursday.
"What we've done is taken the list of substances we provided to owners at the beginning of last year," Steve O'Donnell said. "We've included that in the rulebook. We've also, for a clarity standpoint, included our entire policy in the rulebook for 2010 as well.
"We're going to continue to vigorously and aggressively defend ourselves on behalf of the teams and facts that are out there believing we have the toughest policy in sports. If we can make that better we will, and I believe we've done that this year," O'Donnell said.
The list was added a year after the drug-related suspension of Sprint Cup driver Jeremy Mayfield. At the time, several drug-testing experts questioned the validity of the policy because it lacked a list.
Penn State professor Charles Yesalis, who has written several books on performance enhancing drugs and testified before Congress on legislation related to the control of anabolic steroids and human growth hormone abuse, called the policy without a list "loosey-goosey."
"Red flags in my mind come up all over the place," he told ESPN.com last year. "There has to be a hard and fast list. No ifs, ands or buts. Without it, they can give somebody a pass on something. Nobody does it that way."
Attorneys representing Mayfield, who was suspended after testing positive for methamphetamine, also challenged the validity of the policy without a list.
NASCAR spokesman Ramsey Poston strongly disagreed.
"The policy remains the same," he said Thursday. "The misuse or abuse of any drug is a violation. That remains today. That's still the policy. What we sent to the teams was a sample of what those substances are."
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.