Ports are important to the cartels not so much for the product they send out as for the product they bring in—the precursor chemicals needed to fuel their methamphetamine super-factories, the new maquiladoras. Mazatlán, firmly in the hands of the Sinaloa cartel; Lázaro Cárdenas, contested between the Zetas and La Familia Michoacana; and Matamoros, held by the CDG, are all important inlets for the chemicals that come mostly from China.
