"Law enforcement pressure and strong precursor chemical sales restrictions have achieved marked success in decreasing domestic methamphetamine production. Mexican DTOs, however, have exploited the vacuum created by rapidly expanding their control over methamphetamine distribution -- even to eastern states -- as users and distributors who previously produced the drug have sought new, consistent sources. These Mexican methamphetamine distribution groups (supported by increased methamphetamine production in Mexico) are often more difficult for local law enforcement agencies to identify, investigate, and dismantle because they typically are much more organized and experienced than local independent producers and distributors. Moreover, these Mexican criminal groups typically produce and distribute ice methamphetamine that usually is smoked, potentially resulting in a more rapid onset of addiction to the drug."

Source

National Drug Intelligence Center, "National Methamphetamine Threat Assessment 2007" (Johnstown, PA: US Dept. of Justice, Nov. 2006), p. 1.
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