Heaps of ignominy are not in short order for parties that played sketchy roles in fostering the nation’s deadly opioid abuse and drug overdose crisis. The stain has spread now to one of corporate America’s most-favored advisors — the giant McKinsey consulting group.

The firm has issued a rare public mea culpa for its work with Purdue Pharmaceuticals, a family-run drug maker that has gained notoriety, even among Big Pharma companies, for how it hyped its powerful painkiller OxyContin. The relentless push to sell that drug, officials have asserted, provided a ghastly template for peddling opioids, triggering abuse, addiction, debilitation, and death for hundreds of thousands of Americans in recent times.

Purdue was a McKinsey client, and the consultants now are re-examining their advice to the drug maker on how to fire up OxyContin sales and whether these suggestions fell short of the firm’s own standards. The New York Times, to its credit, dug into records to detail the consultants’ unacceptable conduct, reporting: