Medicare, Medicaid, and private health insurance helped fuel the opioid epidemic because they made it too easy and inexpensive for patients to get opioids, suggests a government-funded study by researchers at Johns Hopkins Bloomberg School of Public Health.

Authors of the study conclude that insurers share responsibility for the massive toll of opioid deaths because they didn’t put in precautions on the drugs to make them harder to access. They covered opioids at a low cost, didn’t discourage their prescribing, and allowed a large volume to be prescribed at once.