One-fourth, or around 1,900 of North Carolina's over 8,100 AIDS cases, are the result of drug users exchanging dirty needles. The Institute of Medicine, a national think tank, proposes a needle-exchange program, whereby drug users can turn in used needles for clean ones. The program is not without its critics, who cite giving drug users drug paraphernalia. There are 100 exchange programs nationwide. North Carolina's only program is in Asheville.