Only six days into the new year, twelve people had overdosed on heroin in the small, mostly white city of Wilmington, Ohio, about an hour southwest of Columbus. Two of those people died, and the rest might have died, too, had paramedics not administered Narcan, a life-saving drug that can reverse the effects of a heroin overdose. For a city of only about 12,500 people, an average of two people overdosing a day is a big deal.

Wilmington isn’t alone. More people died in 2014 from drug overdoses in the United States than in any other year on record. More Americans now die from overdoses than die in car accidents. Heroin and derivative drugs, like OxyContin, account for most of the deaths. (Derivative drugs are called “opioids”; they were all originally derived from the opium poppy.)

A heroin epidemic is devastating the northern Kentucky and Cincinnati area, where I live. From 2014 to 2015, a network of northern Kentucky hospitals witnessed a 44.5 percent increase in overdose visits to emergency rooms. For instance, in November 2014 alone, 55 people landed in the emergency room after overdosing. In November 2015, it was 107. Some months the numbers were even higher. Just as I sat down to write this piece, I noticed an hour-old Cincinnati-area headline: “Mom found dead, Dad ODs at Children’s.” In the hospital room of a seven-month-old child, the mother was found dead and the father unresponsive with a heroin syringe in his arm. Their baby had undergone surgery the previous day.

In his excellent book Dreamland, journalist Sam Quinones traces the remarkable spread of heroin from big cities like New York City into the suburbs and small cities of white America. As he tells the story, two big forces collided.

The first was “the pain revolution,” helped by big pharmaceutical companies like Purdue Pharma, whose salespeople relentlessly touted OxyContin as a virtually addiction-free painkiller. As late as the 1990s, doctors had been wary of prescribing opioids to relieve everyday aches and pains out of concerns about addiction. They prescribed opioids to cancer patients in hospital beds, where they could supervise them. But the idea of sending a patient home with a bunch of opioid pills was deemed too risky.

The pain revolution changed all that. Pain doctors lobbied to make pain the “fifth vital sign,” urging doctors to treat a patient’s complaint about, say, back pain with pain medication. Purdue Pharma, the company that put OxyContin on the market in 1996, had an army of salespeople ready to supply the pills. What their salespeople didn’t know is that they were unleashing a massive new wave of addiction, and, when consumers couldn’t afford (or doctors wouldn’t prescribe) enough OxyContin, a ready-made demand for heroin.

The second force in the spread of heroin was the innovation of poor Mexicans, almost all from the same small town of Xalisco, who wanted to cross the border to get a piece of the American Dream and take it back to Mexico. The Xalisco Boys, as Quinones calls them, learned to sell heroin like pizza. They weren’t a drug cartel or a gang, and the last thing they wanted was violence or drama. They just hoped to sell a good product to their addicted customers, make some money, and a few months later head back to their families in Mexico with a bunch of Levi’s 501s and other American goods, heroes to all.

The Xalisco Boys weren’t even one big business; they operated independently in cities and towns all across America. An enterprising Xalisco Boy, buoyed by success working as an underling in one city, would set off on his own for an undeveloped market like Boise City or Nashville or Columbus and set up shop. He would find some addicts to begin the business, and a few poor young men (or boys) back in Mexico to deliver the heroin. He set up a dispatcher at an apartment to take the customers’ calls; the dispatcher would then call the drivers and tell them where to meet the customer. The driver stuffed a couple dozen uninflated balloons in his mouth, and when he met the customer—in a Walmart parking lot, outside a methadone clinic—he spit out however many balloons the customer had ordered. Each balloon contained pure black tar heroin, straight from the mountains above Xalisco. If a driver got pulled over by a cop, he just swallowed the balloons. (The balloons came back out when the driver went to the bathroom, the black tar intact and no harm done.)

A Xalisco heroin trafficker who developed the Ohio market told Quinones that when he first came to Ohio, he went to Dayton, but eventually left there to focus on Columbus, even though business was hot in Dayton. Why? “We were selling a lot,” he told Quinones. “But the thing I didn’t like in Dayton was we were dealing with a lot of blacks. I don’t deal with blacks if I don’t have to. In the long run they’ll rip you off. They’ll hurt your kids. They’ll pistol-whip you.” He just wanted to lay low. He avoided Florida, too: the heroin market there was dominated by “Colombians and Cubans and Puerto Ricans” who think “they can solve everything by killing. I wasn’t gonna kill nobody over drugs.” White people were safer, he thought.

Thus it is that a bunch of poor Mexican villagers came to supply heroin to whites—primed by OxyContin and hungry for more—in suburbs and small towns and cities. It’s surely not all the result of Xalisco drug dealers, but a heroin and opioid crisis is now rocking middle American states like Ohio and getting the attention of presidential candidates in New Hampshire, which has the third-highest rate of drug overdose deaths among states. Jeb Bush is talking about his daughter’s battle with drug addiction. Chris Christie’s emotional account of a friend from law school dying of a drug overdose has been seen over eight million times.

But don’t let the accounts of politicians and the rich and famous fool you. As I’ll show tomorrow, despite increasing use among wealthier Americans, the heroin crisis still appears to be most severe among poor and working-class whites.