Americans are beginning to understand what the lobbyists for pharmaceutical companies successfully concealed from them for two decades: Factory-made prescription opioids like Vicodin, Percocet, and Oxycontin are basically the same drug as the heroin that street addicts buy from their dealers and inject into their veins. When unsuspecting people get prescribed oxycodone for a knee injury or a surgery, a certain percentage will become addicted. That percentage is high: The Centers for Disease Control reported last March that 13.5 percent of people prescribed eight days of opioids were still using them a year later. Unwarned, any patient can get hooked. It happened to quarterback Brett Favre and to radio host Rush Limbaugh. And the over-prescription of these pills created a massive recreational market. Everyone “knew” that pills, which respectable people took, could never be as dangerous as heroin, which respectable people did not. People of modest means who became addicted to these pills discovered they were prohibitively expensive on the streets. Heroin was affordable.

It is usually the arrival of a “bad batch” of heroin or, increasingly, of fentanyl that causes a mass poisoning of the sort Fairfax just underwent. About three years ago, the street heroin market began to be shaped by a pharmaceutical revolution. Organized crime groups got access to fentanyl, an opioid that had been used since the early 1960s to treat people with terminal cancer. They began to substitute it for heroin, wholly or in part. It was chemists and pharmacists in China and Mexico who produced most of the stuff. An investigation by Britain’s Guardian newspaper found that 80 percent of the fentanyl in the New York area came from Mexico’s Sinaloa cartel, while most of Philadelphia’s was Chinese-made, shipped through Mexico. Between 2014 and 2016 fentanyl seizures sextupled in the United States.