L ONDON BREED , the mayor of San Francisco, recently announced a new drugs task-force, which is the kind of thing mayors do. This task force, though, was unusual because it was not aimed at opioids but at methamphetamine. In 2017 meth overdoses killed 87 people in the city, more than twice as many as heroin. Open-air dealing, uninterrupted by the police, is a common sight in the poor Tenderloin district. Use is widespread among the city’s many homeless. Because the drug induces aggression, frenzy and paranoia, passers-by often feel unsafe. Half the people now admitted for psychiatric emergencies to the city’s general hospital are suffering from the effects of meth-induced psychosis.

The problem is not confined to San Francisco. Although politicians and journalists are understandably transfixed by the 50,000 people killed by opioids each year, the rise in meth-overdose deaths has attracted less attention (see chart). In 2000 only 578 Americans died of an overdose. By 2017, deaths had increased 18-fold to 10,333 people. Meth addiction mostly afflicts western and south-western states like Arizona, Oklahoma and New Mexico, where fentanyl and heroin deaths are less common than in the east. For that reason, states tend to either have a meth problem or an opioid problem—with the exception of West Virginia, which leads the nation in overdose deaths for both.

Much of this deadly surge is caused by supply. Little meth is now made in America. The number of domestic meth labs busted by police dropped from 15,000 in 2010 to 3,000 in 2017. Most of these are amateurish operations that cops call “Beavis and Butthead labs”, incapable of producing more than two ounces of the stuff per batch. “Mexican cartels dominate the market. They manufacture meth in superlabs across the border,” says Chris Nielsen, the special agent in charge of the Drug Enforcement Administration’s ( DEA ) San Francisco division. Left unmolested, the chemists have perfected their technique. The purity of Mexican-produced meth has surged from 39% in 2007 to 97% today. At the same time, competition between cartels has increased supply, quartering prices. “They’re becoming more brazen now. The loads are becoming bigger,” says Mr Nielsen. His division seized 830kg of meth in 2018—47% more than the year before.

Another reason for the meth surge is the growth of so-called polydrug abuse. Half of those who died of meth overdoses in 2017 also had opioids in their system. Users usually have a drug of choice—opioids, which numb feeling, or stimulants such as cocaine and meth. When they cannot cheaply or easily obtain their preferred hit (or if they are afraid that the local batch is tainted), they will often substitute another drug. In robust urban markets, doses of fentanyl-laced heroin or meth can be obtained for as little as $5.

One factor that had limited the spread of meth is that it is a pain to use. Injecting it requires dissolving it in acid and high heat, which then damages veins. Smoking it harms the lungs. But that too may now be changing, as manufacturers are experimenting with putting the drug in pill form. A husband and wife were recently arrested for running a meth-pill operation from their business, a care home in Vallejo, California. They had 31lb of pills embossed with reproductions of American icons like the Kool-Aid man, Tesla and Donald Trump. Widespread introduction of such pills would not just make the drug easier to take; it could also be sold as a party drug to unsuspecting youngsters.

In San Francisco, where the death rate in 2017 was nearly triple the national average, rates of use are especially high among gay residents, who take it as a party drug, and the homeless. Its cheapness has accelerated “a problem that has existed for decades among the LGBT community around meth use,” says Raphael Mandelman, a member of the city’s board of supervisors. It is also used by “folks who are homeless who are trying to get through a cold night or stay awake,” he says.

Like opioids, meth is highly addictive and difficult to quit. But unlike opioids, it lacks effective pharmacological treatments. There is no approved medication-assisted treatment for addiction which substantially decreases the chance of relapse. There is also no equivalent of naloxone, a life-saving drug that reverses an opioid overdose. Meth kills by overloading blood vessels, eventually resulting in aneurysms, heart failure and strokes. As a result, longtime older users are likeliest to die—in San Francisco, the average age of those who die of a meth overdose is 49.