colorado springs, colorado (ap)

The U.S. Anti-Doping Agency (USADA) is intensifying its education programme for athletes heading to the Beijing Olympics, reminding them of rules and emphasising the need for athletes with special exemptions to get their paperwork in order.

The agency wants to be sure athletes are familiar with International Olympic Committee rules that govern the games, which begin August 8.

Recently, the issue of "therapeutic use exemptions" has come up. Some athletes are allowed to take prescribed medicine that is on the banned-substance list, but only if an exemption form has been completed.

Over the past month, USADA has issued public warnings to three athletes for failing to file the proper paperwork. The most notable was gymnast Morgan Hamm, who took a prescribed anti-inflammatory shot without proper clearance. The US gymnastics federation has cleared him to compete at the Olympics and is looking for that decision to be confirmed tomorrow by the International Gymnastics Federation.

The other two warnings came because athletes - women's basketball player Rebekkah Brunson and heptathlete Ryanne DuPree - failed to file for exemptions for prescribed asthma medication.

Asthma sufferers would be expected to encounter more problems if pollution in Beijing does not clear substantially.

"In our mind, we've done everything possible to make sure athletes don't make technical mistakes," USADA CEO Travis Tygart said Thursday. "Hopefully, they're all on notice, and hopefully they'll comply."

USADA has been running web-based seminars to educate athletes about doping rules.

Tygart has also been in contact with many athletes to explain rules and answer specific questions.