Police and sheriff’s departments in states that produce much of the nation’s methamphetamine have made a sudden retreat in the war on meth, at times virtually abandoning pursuit of the drug because they can no longer afford to clean up the toxic waste generated by labs.

Despite abundant evidence that the meth trade is flourishing, many law enforcement agencies have called off tactics that have been used for years to confront drug makers: sending agents undercover, conducting door-to-door investigations and setting up stakeouts at pharmacies to catch people buying large amounts of cold medicine.

The steep cutbacks began after the federal government in February canceled a program that provided millions of dollars to help local agencies dispose of seized labs. Since then, an Associated Press analysis shows, the number of labs seized has plummeted by a third in some key meth-producing states and two-thirds in at least one, Alabama.

The trend is almost certain to continue unless more states find a way to replace the federal money or to conduct cheaper cleanups.

In Michigan, authorities still bust meth labs when they find them, but tougher missions like secretly sending officers into the meth underworld have been scrapped.

“They’re not actively out there looking for it,” said Tony Saucedo, meth enforcement director for Michigan State Police. “And the big issue is money. We have taken 10 steps backward.”

Authorities say they have no doubt that meth trafficking remains brisk. Record busts are being reported in some states that fund their own cleanups.

But in places that rely on federal money, law enforcement agencies feel paralyzed. At least one sheriff became so frustrated that he considered burning meth waste illegally in a landfill rather than leaving it in neighborhoods where curious children could find it.

In Warren County, Tenn., about 70 miles southeast of Nashville, deputies had “always been very aggressive on meth,” Sheriff Jackie Matheny said. By midsummer a year ago, they had busted some 70 meth labs. This year, that number tumbled to 24.

“When you have to kind of kick it into neutral, it makes you sick to your stomach because we know it’s out there,” Matheny said.

Making matters worse, sheriffs say, was the suddenness of the loss, which didn’t give cash-strapped local governments any time to come up with another way to pay for cleanups that typically cost $2,500 to $5,000 per lab.

“We didn’t have an opportunity to prepare,” Matheny said. “We just got a phone call saying, ‘You’re not going to have funds anymore.’ It just absolutely crippled us.”‘

The AP analysis involved building a database of lab seizures in the nation’s top 10 meth-producing states based on 2010 figures. Combined with numbers from the first half of 2011, the statistics showed that seizures had dropped sharply in states that depended on federal money. Yet busts were skyrocketing in states that pay for their own cleanups.

The AP also conducted 50 to 60 interviews to confirm the trend, speaking with police officers, sheriffs and meth-lab specialists in many of the top 10 states.

Lab seizures were down 32 percent through May 31 in Tennessee, which led the nation in seizures in 2010. The numbers were similar or worse in other leading meth states: down 33 percent in Arkansas, 35 percent in Michigan and 62 percent in Alabama.

All of those states relied heavily on funding from the federal Community Oriented Policing Services, or COPS program. It offered local agencies $19.2 million in 2010. That money was not renewed and is unlikely to come back.

“Do you really think our labs fell that much?” asked Tommy Farmer, state meth task force coordinator for Tennessee. “Hell no.”