A popular Web story about meth-tainted propane tanks has made its way to some York County in-boxes, causing concern about the safety of those tanks during the middle of the summer grilling season.

But is there anything to worry about?

Possibly, local drug agents say, but not likely.

The e-mailed rumor says methamphetamine makers get their propane tanks from exchanges at supermarkets and convenience stores. The drug producers empty propane from the tanks and fill them with anhydrous ammonia, an ingredient used to concoct meth.

Knowing the ammonia will damage a tank's valve, meth cooks exchange their tanks, which are then refilled with propane. The propane adds pressure to a weak valve and could cause an unsuspecting consumer's grill to explode.

That scenario is possible, authorities say, but neither state nor local officials have ever investigated such a case.

"The chances are very slim," said Lt. Max Dorsey, an Upstate narcotics supervisor with the State Law Enforcement Division. "But it's good that the public ... realize the potential for danger."

When he exchanges propane tanks, Dorsey said he always looks for the telltale sign of meth use: The tank's valve is a bluish green. This discoloration comes from the ammonia, which is commonly used in the refrigeration industry. It can burn skin or become fatal if inhaled.

Meth production first became popular in Midwestern states because that ammonia was available in the fertilizer used on large farms, Dorsey said. The drug gradually spread across the country.

Not as widespread locally

But meth cooking, Dorsey said, isn't as prevalent in York, Chester and Lancaster counties as it is in Upstate areas such as Greenville and Pickens.

The last meth lab discovered in Chester County was two years ago, said Scott Thompson, a narcotics investigator with the Chester County Sheriff's Office. That county doesn't have as much anhydrous ammonia as other farming communities.

Like Chester, most meth in York County also is imported, said Marvin Brown, head of the county's drug unit. And even if a damaged tank should find its way into an exchange crate, a quick glance should give it away.

"Once they use them, usually the tanks are pretty beat up and real blue around the top," Brown said. "It's pretty obvious they've been used for something they shouldn't be used for."

Not only would the tanks be obvious to consumers, Dorsey said, meth makers are more likely to steal a tank than exchange one.

National concern

But the Internet chatter suggests meth tanks are daily popping up in America's back yards, said Chris Hartley, vice president of marketing for Blue Rhino, which sells propane tanks at 42,000 stores across the country.

The reality, he said, is the Winston-Salem, N.C.-based company inspects millions of tanks each year and finds only a handful that have been used in meth production.

The company, he said, has never allowed a tainted tank to reach a customer's hands.

"I'm not really sure what triggered this Internet legend," Hartley said. "Certainly, there's a grain of truth in the fact that people are using propane tanks for meth production. But the other pieces of the story are really legend."