A new method for making methamphetamine requires less technical knowledge and fewer over-the-counter cold pills, presenting a new challenge to law-enforcement officials, the Associated Press reported Aug. 24.

Methamphetamine users are reportedly making small batches of the drug for their own use with the so-called "shake and bake" approach. The method requires only a two-liter soda bottle, a small number of over-the-counter cold pills containing pseudoephedrine, and a few household chemicals -- far less complicated than the dirty and dangerous process used at clandestine meth labs where larger quantities of the drug are typically produced.

However, the new method remains hazardous: drug batches are smaller, but the mix of chemicals in the soda bottle can still explode. "If there is any oxygen at all in the bottle, it has a propensity to make a giant fireball," said Sgt. Jason Clark of the Missouri State Highway Patrol's Division of Drug and Crime Control. "You're not dealing with rocket scientists here anyway. If they get unlucky at all, it can have a very devastating reaction." A number of burn cases have been linked to the shake-and-bake method, experts said.

Not only can the meth-making tools now be carried in a small bag, the method requires such a small amount of cold pills that users can dodge limits on sales of pseudoephedrine-based drugs imposed at the height of the meth epidemic.

Officials in the Midwestern U.S. fear that the new meth-production method is fueling a recent increase in use of the drug, which had declined after the initial crackdown on meth labs and restrictions on meth-making chemicals.