WASHINGTON, Mo. -- Three months after the town instituted a law requiring the sale of a key meth precursor by prescription only, police are seeing a ripple effect: Sales of products with pseudoephedrine are down not only in Washington but in surrounding communities, too.

The Washington Missourian reported that in the 90 days before July 7, the date the law took effect, 4,346 boxes of medicine containing pseudoephedrine were sold at the town's five pharmacies. In the first 90 days after, 310 boxes were sold -- a decline of nearly 93 percent -- according to statistics from the Franklin County Narcotics Enforcement Unit.

Sales at pharmacies in four nearby towns -- Eureka, Union, Owensville and Sullivan -- dropped 1.4 percent. Police say that is evidence that methamphetamine-makers who sent friends to buy pseudoephedrine to get around state and federal laws limiting how much pseudoephedrine can be legally purchased -- a practice known as "smurfing" -- are turning to other areas.

"This is phenomenal," task force commander Jason Grellner said. "It's like a pebble in a lake. The Washington experience is having an effect on smurfing throughout the entire area."

Washington sits in Franklin County, which annually ranks among the top counties in the nation in terms of methamphetamine lab crimes and seizures.

The entire state of Oregon requires pseudoephedrine-based products to be sold by prescription only, but Washington became the first town in the U.S. with its own law. Union, also in Franklin County, adopted a similar law earlier this month.

"Now, with Washington and Union pharmacies off-limits, it's easier to go smurfing in St. Louis or Jefferson counties where there are multiple outlets," Grellner said.

That neighboring towns are not only not seeing increases in sales, but are actually seeing decreases, is evidence that the majority of pills were going to meth labs, he said.

"It's all about the money," Grellner said. "We knew all along that the biggest percentage of pseudoephedrine sold was being smurfed for meth labs, but we never had the numbers to prove it. Now we do."

Opponents of the prescription-only laws say they cause an inconvenience for those who have colds and allergies, who now have to get a doctor's OK.

But Grellner and other proponents say people who need those medicines are adapting to the change.

"The people who truly need it are getting it. That shows in the Washington numbers," he said.