Doctors at the Mayo Clinic examined samples of lung tissue from 17 patients, all of which looked as if the people had been exposed to toxic chemicals, the researchers said. Their findings are based on samples of lung tissue from 17 patients around the country whose biopsy specimens were sent to Mayo to be examined under the microscope by experts in lung pathology. Two samples came from patients who died. “All 17 of our cases show a pattern of injury in the lung that looks like a toxic chemical exposure, a toxic chemical fume exposure, or a chemical burn injury,” said Dr. Brandon T. Larsen, a surgical pathologist at the Mayo Clinic in Scottsdale, Ariz. “To be honest, they look like the kind of change you would expect to see in an unfortunate worker in an industrial accident where a big barrel of toxic chemicals spills, and that person is exposed to toxic fumes and there is a chemical burn in the airways.” The injuries also look like those seen in people exposed to poisons like mustard gas, a chemical weapon used in World War I, he said. The findings were published on Wednesday in The New England Journal of Medicine and involved samples from 13 men and four women whose ages ranged from 19 to 67. About 70 percent had a history of vaping marijuana or cannabis oils. Eleven were in Arizona, five in Minnesota and one in Florida. Get the full story at nytimes.com.