In just 10 months, the sixth-largest company in America shipped more than 3 million prescription opioids — nearly 10,000 pills a day on average — to a single pharmacy in a Southern West Virginia town with only 400 residents, according to a congressional report released Wednesday. McKesson Corp. supplied “massive quantities” of the painkiller hydrocodone to the now-shuttered Sav-Rite Pharmacy in Kermit, even after an employee at the company’s Ohio drug warehouse flagged the suspect pill orders in 2007, the report found. That year, McKesson — ranked 6th in the Fortune 500 — reviewed its customers, including Sav-Rite, and reported...