Gov. Arnold Schwarzenegger on Monday signed into law what some advocates describe as one of the state's most important public health policies in two decades - a five-year experiment to reduce the spread of AIDS and other diseases among intravenous drug users by making needles and syringes available without a prescription.

They also cite studies that suggest access to clean needles decreases the spread of disease. And they argue that fiscal conservatives could support such programs because, unlike needle exchanges, they cost government nothing and have the potential to save taxpayers money by reducing medical bills.