Opioid addiction is an epidemic sweeping America, and in a special episode of Last Week Tonight on Sunday, John Oliver shone a light on the years of misinformation that has led to a prescription-fueled crisis. Pharmaceutical companies, pushing painkillers, have created heroin addicts as patients struggle to afford their pill addiction, turning to cheaper, illegal drug alternatives.

“There is no one simple answer here,” Oliver said. “This is going to take a massive effort and a significant investment. It won’t be quick, it won’t be cheap, and it won’t be easy.”

Oliver highlighted the years drug giant Purdue spent pushing Oxycontin. As recently as the early ‘90s, doctors were unsure about prescribing opioids, fearing their addictive nature. The company cited a claim that less than one percent of patients become addicted to opioids: The source of that fact was a single letter in the New England Journal of Medicine.

“Letters pages are not a solid source of information,” Oliver said, pointing to an October 2016 letter to the Williamsport Sun-Gazette. The writer questioned whether Clinton would be suitable for office as, sometimes, “that time of the month” would come. “One, she’s 68, and two, fuck you!” Oliver said.

By 2000, doctors were writing nearly 6 million Oxycontin prescriptions per year, but in 2007, Purdue was punished for lying to the public. The company had to pay $634 million in settlement fees. Cephalon, a competitor, was also made to pay a $444 million settlement. Despite this, Purdue’s marketing of Oxycontin has still been drawn into question: an LA Times investigation found that Oxycontin lasted less than the 12 hours claimed, eventually leading to withdrawal symptoms.

Today, there are nearly 250 million prescriptions for opioids written annually. The result of the addictions that arise from these prescriptions has been devastating. In one case in Huntington, West Virginia, there were 28 overdoses in one five hour time span. “America is in the midst of a new drug crisis and it seems no one is safe from it,” Oliver said.

Last Week Tonight airs every Sunday evening on HBO.

Photos via Last Week Tonight/YouTube