The ease with which methamphetamine can be manufactured is a major contributing factor to the increase in its use. Law enforcement officials identify and close hundreds of clandestine methamphetamine labs each year. Large operations produce methamphetamine in Mexico and California. Outside of these areas, small rural laboratories are more common.
Rural areas are popular sites for production because strong odors are produced during manufacture.
The manufacture of methamphetamine is simple because it does not require agriculture, specialized equipment, or advanced technical training. Congress enacted the Methamphetamine Control Act of 1996 to curb the production and abuse of methamphetamine by controlling the key chemicals necessary to produce the drug and by increasing criminal sentences for its possession and distribution. Hydroiodic acid is a necessary ingredient in one of the major manufacturing processes. Although strictly controlled, it can be created by combining red phosphorous and iodine - chemicals that are not regulated. Recently, phenylpropanolamine has been used as a precursor chemical to produce amphetamine.