Illicitly manufactured meth is usually made by combining ephedrine or pseudoephedrine with other chemicals that are often poisonous or highly flammable. The mixture is then added to a solvent such as gasoline and heated to crystallize.

Because illicit methamphetamine production is not regulated or supervised, and there is no quality control process, any number of cutting agents could conceivably be added to the process to dilute the drug.

The heating process is particularly dangerous, as there is significant risk of fire and explosion. The waste materials left behind are also highly unstable and combustible. According to the U.S. Forest Service, 1 pound of meth produces up to 6 pounds of toxic waste.

There are many detrimental health effects associated with operating a meth lab. Inhaling fumes during methamphetamine production can cause significant lung damage and other respiratory issues, while handling the various corrosive or poisonous chemicals can damage the skin and eyes.