Methamphetamine (meth), a drug with limited medical use and high potential for abuse and addiction, is a subject of widespread concern. Once associated mainly with the West Coast and white, male, blue-collar workers, illicit meth is now used by diverse population groups nation-wide, with concentrations in the West, Southwest, and Midwest. Meth is supplied primarily by clandestine labs in California and Mexico. The drug is relatively simple to make from easily obtained recipes, but access to certain ingredients has become more difficult. Meth production in small, toxic labs (STLs) increased initially due to the successful closure of some "super-labs" (labs capable of making more than 10 pounds of meth in a 24-hour cycle), relative ease of making meth, continuing demand for the drug, and desire for potential wealth and involvement in a criminal underground social activity. Although the greater fraction of meth used and distributed across the nation comes from super-labs, the sheer number of STLs, their geographic diffusion, and their residual impacts have prompted concern across a wide spectrum of the country.