In this photo taken Friday, Aug. 14, 2009, a display of items
TULSA, Okla.—This is the new formula for methamphetamine: a two-liter soda bottle, a few handfuls of cold pills and some noxious chemicals. Shake the bottle and the volatile reaction produces one of the world's most addictive drugs.

Only a few years ago, making meth required an elaborate lab—with filthy containers simmering over open flames, cans of flammable liquids and hundreds of pills. The process gave off foul odors, sometimes sparked explosions and was so hard to conceal that dealers often "cooked" their drugs in rural areas.

But now drug users are making their own meth in small batches using a faster, cheaper and much simpler method with ingredients that can be carried in a knapsack and mixed on the run. The "shake-and-bake" approach has become popular because it requires a relatively small number of pills of the decongestant pseudoephedrine—an amount easily obtained under even the toughest anti-meth laws that have been adopted across the nation to restrict large purchases of some cold medication.

"Somebody somewhere said 'Wait this requires a lot less pseudoephedrine, and I can fly under the radar,'" said Mark Woodward, spokesman for the Oklahoma Bureau of Narcotics and Dangerous Drugs Control.

An Associated Press review of lab seizures and interviews with state and federal law enforcement agents found that the new method is rapidly spreading across the nation's midsection and is contributing to a spike in the number of meth

cases after years of declining arrests.

The new formula does away with the clutter of typical meth labs, and it can turn the back seat of a car or a bathroom stall into a makeshift drug factory. Some addicts have even made the drug while driving.

The pills are crushed, combined with some common household chemicals and then shaken in the soda bottle. No flame is required.

Using the new formula, batches of meth are much smaller but just as dangerous as the old system, which sometimes produces powerful explosions, touches off intense fires and releases drug ingredients that must be handled as toxic waste.

"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