SULLIVAN COUNTY, Tenn. -

Criminals are using a new and more potent synthetic drug that resembles bath salts.

It's called gravel, and police say it's one the fastest growing drug problems in our region.

News 5 checked in with law enforcement to find out what's behind recent arrests after laws went into effect last year making the sale of bath salts illegal, many drug users are now turning to gravel, also known as Alpha PDD, to get their fix.

Police tell us they making more and more arrests every day. "I would go as far to say it's really an epidemic," said Leslie Earhart, SCSO public information officer.

Earhart tells us the illegal substance known as gravel is taking over the Tri-Cities. "Some people still refer to it as bath salts, other people call it gravel. It's basically the same thing, but the chemical makeup is different than the original bath salts that you heard so much about a couple of years ago," said Earhart.

We learned the dangerous drug is known for its hallucinogenic high. A single gram goes for about $200.

Earhart tells us that drug dealers are purchasing gravel from North Carolina and other areas of Virginia, and then they are bringing it to our region. "In this region not just Sullivan County, we know of nine overdoses that are possibly connected to gravel now those are the overdoses that have resulted in death. There are not confirmed just yet, because we are awaiting autopsy results," said Earhart.

Just on Monday law enforcement arrested seven people in Greene County on drug-related charges involving bath salts and gravel.

District attorney Barry Staubus tells us many of these are offenses are now being handled on the federal level as well as locally.

"We look at the potential punishment, we also look at the jurisdictional aspect that means the federal government can look at international distribution and regional distribution. We look at all of these things when try to determine whether are not we are going to prosecute these cases," said Barry Staubus.