The case study, published in the European Respiratory Journal, suggests the condition in the lungs of an unnamed 49-year-old woman was likely caused by vaping. Hard-metal pneumoconiosis can result in permanent scarring, breathing difficulties and chronic coughing. The woman vaped cannabis oil - which has been linked to many of the hundreds of cases of lung illness in the US have been linked to. One of the authors of the case study, Kirk Jones [...] said: "Hard-metal pneumoconiosis is diagnosed by looking at a sample of patient's lung tissue under the microscope.