NEW YORK—Baristas at a Starbucks Corp. location in Buffalo, New York, walked off the job for a second day on Thursday in protest of what they say are unsafe working conditions amid a new rise in COVID-19 cases. Workers left their positions on Wednesday at the Elmwood Avenue location—the only unionized corporate-owned Starbucks store in the United States—and say they will not return until they feel safe. A third of employees there are out because of COVID-19, said barista Casey Moore, one of the union organizers in Buffalo. “The store is drastically understaffed, leaving the remaining partners exhausted and overworked,” she said. Company spokesman Reggie Borges said that as of Monday, all 20 Buffalo-area stores had closed seating areas and switched to take-out only, and some had reduced hours of operation, to address a local spike in COVID-19 cases and staff shortages. “Throughout the pandemic we have met and exceeded …