Even with a Joliet, Ill., drug treatment physician, publicly stating that he's seen as many as four users of Krokodil, the DEA is not sounding the alarm.
The drug, which is made by cooking codeine with various chemicals, such as lighter fluid, gasoline and industrial cleaners, was first reported in 2011.
It's been on the radar, with Krokodil reports in the U.S. making news lately.
Still, federal officials say they are skeptical that the nightmare drug, a cheap heroin knockoff, that originated in Russia has reached American soil.
“We, the DEA, are not seeing cases of it,” agency spokeswoman Dawn Dearden told Fox News Thursday. “Nothing’s been turned into any of our labs."
"As far as the DEA is concerned, we have not seen any cases.”
The agency is not actively investigating the latest report of the users in Illinois or a report that surfaced late last month in Arizona, Dearden said.
Dr. Abhin Singla, director of addiction services at Presence Saint Joseph Medical Center in Joliet, was the man who drew attention to it this week.
He has treated people for a drug that he says leaves users with gangrenous limbs, scaly, rough skin and an addiction often far too powerful to overcome.
"If you want to kill yourself, (using) this is the way to do it," said Singla.
Jan Ciccarelli, a spokeswoman for the treatment center, told Fox News later Thursday that a fourth user of the drug has potentially been identified.
Two of the initial three patients, she said, have left the center against the advice of doctors. The original three patients were women under age 25.
Their arms and legs were significantly maimed from gangrene. Two of them are acquaintances, so it’s possible they received the drug from the same source.
None of the patients would indicate where it was obtained. Singla said one woman likely faces years of surgeries if she is ever able to walk again.
"It's a horrific way to get sick,” he continued.
“The smell of rotten flesh permeates the room. Intensive treatment and skin grafts are required, but they are often not enough to save limbs or lives."
While three times more potent than heroin and roughly one-third of the cost, Singla said the “high” produced from the drug only lasts a few hours.
As far back as 2011, DEA officials acknowledged that they were monitoring the potent drug overseas, but had not verified its presence in the U.S.