This photo provided by the U.S. Drug Enforcement Administration's Phoenix Division shows some of the 30,000 fentanyl pills the agency seized in one of its bigger busts, in Tempe, Ariz., in August, 2017. Credit: Drug Enforcement Administration via AP

By now, policymakers have surely heard about the opioid crisis that has gripped the nation since at least 2010. In 2017, more than 47,000 Americans lost their lives to opioids. While China has to this point been the predominate exporter of opioids to the US, the market is changing.

Officials from Beijing, some of whom were in D.C. recently for trade negotiations, have promised to crack down on fentanyl-like narcotics while just this past January US Customs and Border Protection agents seized a record amount of fentanyl at the US-Mexico border. This change is evidence that, as the illicit-drug market shifts, so must our strategy.

Until about 2000, the problem of opioid addiction had mostly been confined to heroin addicts in certain inner-city communities. Fatal overdoses of prescription opioids began a steady upward trend from about 3,500, until they nearly plateaued in 2007, at just under 13,000 fatalities. This expansion was initially fueled by increasing availability of prescription opioids such as Oxycontin. But this crisis — and it is a crisis — is now being driven by the importation of very strong synthetic opioids, especially fentanyl.

Fentanyl is 50 times stronger than heroin, its morphine-based cousin. It is very often mixed with heroin before being sold on the street to addicts who seek a stronger (and more lethal) opioid cocktail. The introduction of fentanyl into the street-level opioid supply chain has spiked opioid overdoses both in number and lethality. Fentanyl is the reason that naloxone, an effective opioid antidote, is now being carried by everyone from meter readers to suburban parents.

Fatal opioid overdoses have increased five-fold since 2010, but the rate of increase accelerated sharply in 2014. This increase, attributable to the introduction fentanyl into the heroin supply, doubled the rate of fatal overdoses from 2014-2017. The continued acceleration of fatal overdoses presents a clear and rapidly growing threat to the public health in United States.

But where does this particular poison come from? Fentanyl is entirely synthetic, and its production occurs in a laboratory. Unlike heroin, cocaine and marijuana, fentanyl does not require the cultivation of any plant material. This factor, along with its potency and relatively small profile packaging, make fentanyl an ideal substance for foreign exporters to send to the US

Most fentanyl is produced in China and exported via mail and then through a complex network of freight forwarders and through multiple transfers that are almost impossible for authorities to track. The US government has recognized for some time that most synthetic opioids enter the US in the mail from China. The Trump administration has sought to crack down on this by asking China to more closely regulate the manufacture of opioids, as well as by requiring advance electronic information for parcels shipped from China.

Notwithstanding China’s leadership in the synthetic opioid market, there is mounting evidence that production of fentanyl in Mexico near the southwest border of the US is expanding. Seizures of fentanyl at the San Diego and Tucson ports of entry, for example, nearly quadrupled between 2016 and 2017. At the same time, demand for Mexico’s heroin has softened because of the increased availability of the stronger, cheaper substitute: fentanyl. As demand for heroin from Mexico continues to soften and the US government increases its effort to stem the flow of fentanyl from China, Mexican criminal syndicates will further ramp up fentanyl production and export to the US

The Sinaloa Cartel has already established itself as a leading Mexican producer and exporter of fentanyl to the US Its ability to produce fentanyl was confirmed by the discovery of a production laboratory in a remote part of territory under Sinaloa control. If its drug-exporting activity can be judged by seizures at the US border, the frequency and volume of fentanyl seizures at the San Diego and Tucson ports of entry signal a renewed effort by the Sinaloa Cartel to fill any void in supply created by new regulations aimed at China.

So, what does all this mean? In addition to having a crisis in the volume of foreign nationals entering the southwestern border seeking asylum through the back door, our ports of entry are increasingly becoming a key battleground in the war against opioids.

Congress must act aggressively to ensure the Drug Enforcement Administration and US Customs and Border Protection have the resources they need to prevent opioids from pouring across the southwest border. Because of the clear and present danger to millions of Americans, there must be zero tolerance for any individual trafficking in this poison that has tragically cut short so many lives and brought misery and despair to many, many others.

Jason Johnson is president of the Law Enforcement Legal Defense Fund and a former deputy commissioner of the Baltimore Police Department.