But Mr. Van Haaften, like officials in other states with similar restrictions, is now worried about a new problem: the drop in home-cooked methamphetamine has been met by a new flood of crystal methamphetamine coming largely from Mexico.
Sometimes called ice, crystal methamphetamine is far purer, and therefore even more highly addictive, than powdered home-cooked methamphetamine, a change that health officials say has led to greater risk of overdose. And because crystal methamphetamine costs more, the police say thefts are increasing, as people who once cooked at home now have to buy it.
The University of Iowa Burn Center, which in 2004 spent $2.8 million treating people whose skin had been scorched off by the toxic chemicals used to make methamphetamine at home, says it now sees hardly any cases of that sort. Drug treatment centers, on the other hand, say they are treating just as many or more methamphetamine addicts.
And although child welfare officials say they are removing fewer children from homes where parents are cooking the drug, the number of children being removed from homes where parents are using it has more than made up the difference.
"It's killing us, this Mexican ice," said Mr. Van Haaften, a former sheriff. "I'm not sure we can control it as well as we can the meth labs in your community."
The influx of the more potent drug shows the fierce hold of methamphetamine, which has devastated many towns once far removed from violent crime or drugs. As Congress prepares to restrict the sale of pseudoephedrine, the cold medicine ingredient that is used to make methamphetamine, officials here and in other states that have recently imposed similar restrictions caution that they fall far short of a solution.
"You can't legislate away demand," said Betty Oldenkamp, secretary of human services in South Dakota, where the governor this month proposed tightening a law that last year restricted customers to two packs of pseudoephedrine per store. "The law enforcement aspects are tremendously important, but we also have to do something to address the demand."
Here, officials boast that their law restricting pseudoephedrine, which took effect in May, has been faster than any other state's in reducing methamphetamine laboratories. Still, when Mr. Van Haaften, director of the Governor's Office of Drug Control Policy, surveyed the local police, 74 percent said that the law had not changed demand, and 61 percent said supply had remained steady or increased.
In a survey of treatment professionals, 92 percent said they had seen as many or more methamphetamine addicts; the state treated 6,000 in 2005 and expects to treat more than 7,000 this year, based on current trends. Some health officials said abuse among women, typically the biggest users of methamphetamine, was rising particularly fast.
While seizures of powdered methamphetamine declined to 4,572 in 2005 from 6,488 in 2001, seizures of crystal methamphetamine increased, to 2,025 from one.
Federal drug agents tend to describe ice as methamphetamine that is at least 90 percent pure. Officials here say much of their crystal methamphetamine is less pure - "dirty ice," they call it. But either is far more potent than homemade powdered methamphetamine; a "good cook" yields a drug that is about 42 percent pure, but around 25 percent is more common. And in the first four months after the law took effect here, average purity went to 80 percent from 47 percent.
Other states have seen the same.
"The Mexican drug cartels were right there to feed that demand," said Tom Cunningham, the drug task force coordinator for the district attorneys council for Oklahoma, the first state to put pseudoephedrine behind pharmacy counters, in 2004. "They have always supplied marijuana, cocaine, and heroin. When we took away the local meth lab, they simply added methamphetamine to the truck."
A methamphetamine cook could make an ounce for $50 on a stovetop or in a lab in a car; that same amount now costs $800 to $1,500 on the street, the police say.
"Our burglaries have just skyrocketed," said Jerry Furness, who represents Buchanan County, 150 miles northeast of Des Moines, on the Iowa drug task force. "The state asks how the decrease in meth labs has reduced danger to citizens, and it has, as far as potential explosions. But we've had a lot of burglaries where the occupants are home at the time, and that's probably more of a risk. So it's kind of evening out."
When the state surveyed the children in state protection in southeastern Iowa four months after the law took effect, it found that 49 percent were taken from parents who had been using methamphetamine, the same percentage as two years earlier, even as police said they were removing fewer children from homes with laboratories.
Some law enforcement officials say that addicts may find the crystal form more desirable. "If they don't have to mess with precursor chemicals, it's actually a bit easier on them, and safer," said Kevin Glaser, a drug task force supervisor for the state highway patrol in Missouri, which last year led the nation in methamphetamine lab seizures.
But the switch has also increased the risks. "People are overdosing; they're not expecting it to do this much," said Darcy Jensen, director of Prairie View Prevention Services in South Dakota. "They don't realize that that fourth of a gram they're used to using is double or triple in potency."
Federal officials say there are 1.4 million methamphetamine addicts in the United States, concentrated in the West, where the drug began to take hold in the late 1980's, and the Midwest and South, where it moved in the mid- and late 1990's.
Drug enforcement officials have always said that 80 percent of the nation's supply comes from so-called super labs, those able to make 10 pounds or more. But in some counties here, officials say that all the methamphetamine came from mom-and-pop labs that made the drug by cooking pseudoephedrine with toxic farm and household chemicals.
Law enforcement focused on the laboratories because they were so destructive: the police found children who had drunk lye thinking it was water, or went without food as parents went through the long binge-and-sleep cycles of using. Laboratories in homes, motels, abandoned farm buildings or cars frequently exploded, or dumped their toxic chemicals into drains or soil. Small police departments spent much of their time attending to contaminated sites.
More than 30 states have restricted pseudoephedrine in some way. Nine have put it behind pharmacy counters, and Oregon now requires a prescription to obtain it.
Addicts and cookers have proved to be skilled at getting around the restrictions; as one state imposes a law, bordering states see an increase in laboratories. Oklahoma recently linked its pharmacies by a computer database to track sales after discovering that cooks were going county-to-county buying from several pharmacies a day.
Iowa's law passed unanimously. As in other states, officials say the number of laboratories had already begun to decline, most likely because cooks feared they would be caught because there was so much public attention on the problem.
The law resulted in a decline of at least 80 percent. Police found 138 laboratories from June to December, down from 673 for the same period the year before. The state had hit a high of 1,500 lab busts in 2004, but with the law, had 731 for 2005, and expects just 257 this year. Law enforcement says the costs of policing and cleaning up labs will drop to $528,000 next year from $2.6 million in 2004.
But here and in many of the states with recent pseudoephedrine restrictions, frustration with the stubborn rate of addiction has moved the discussion from enforcement to treatment and demand reduction.
That discussion, officials say, will be much tougher.
After listening to Mr. Van Haaften's report on the effects of the law this week, State Representative Clel Baudler, a former state trooper who now heads the public safety committee for the Iowa General Assembly, charged his committee to come back to the next meeting with strategies to reduce demand.
"My fear is, when I ask what they think we should do, they'll say 'I don't know,' " Mr. Baudler said in an interview afterward. "We've increased penalties, we've increased prison time, we're still not getting in front of it."
Officials say they never advertised the law as one that would reduce methamphetamine addiction. Still, they are surprised at how the drug has hung on.
"Things that are highly destructive, including diseases, tend to be self-limiting," said Arthur Schut, president of the Mid-Eastern Council on Chemical Abuse in Iowa City, and a member of the state's drug policy advisory council. "This has been devastating. It's remarkable how quickly people are damaged by it."
Mr. Van Haaften, too, knows that it was too much to hope that the law would reduce demand. Still, he says, "I had a little hope."
"I knew of the addictive nature, but in my heart, I believed people didn't want to deal with dealers," he said. "They have guns, it's dangerous, if you make your own it's safer. I hoped for a dip, but the availability did not allow that to happen."
