Move over, fentanyl. Law enforcement officials in the United States are reporting that an even more potent and deadly opioid called carfentanil is coming out of China and being used in heroin on the streets. 

The drug, which is up to 10,000 times more potent than morphine and up to 5,000 times more powerful than pure heroin, is now being blamed for a record spike in drug overdoses across the country, the St. Charles Herald Guide reports. The drug is so powerful that even inhaling it or absorbing it through a cut can be fatal.

According to international drug authorities, carfentanil’s intended use is as a tranquilizer for large animals, such as elephants. The drug is legal in China, which has made it easily exploitable by drug dealers abroad, who ship it into countries where opioid addiction is common. Law enforcement officials say carfentanil generally enters the U.S. via FedEx or mail delivery and wherever it goes, overdoses seem to spike in epidemic proportions.

For example, police officers in St. Charles, Louisiana, a town of almost 53,000 people on the banks of the Mississippi River, are reporting nearly half a dozen overdose calls per day. They’re blaming carfentanil for the increase, calling it “the latest addition to an already growing and costly problem.”

The entrance of carfentanil into the United States comes in the midst of a growing opioid epidemic, in which drug users are increasingly using heroin as a cheap alternative to prescription drugs. Often, these street drugs are laced with cheaper but more powerful opioid alternatives—most commonly, fentanyl—to help make the drugs stronger while driving prices down.

The danger in this is that drug users don’t always know what they’re taking, which has driven a massive spike in overdose deaths across the country. Today, more people die of opioid overdoses in the United States than car crashes, with heroin-like drugs taking an estimated 18,893 lives in 2014 alone. In addition to overdose deaths, increased injection drug use carries a risk of spreading infectious diseases, such as HIV and hepatitis C virus (HCV).

The U.S. government has approached Chinese officials about controlling the drug, which is being compared to a nerve agent. However, no moves have been made to restrict it so far.