Many of us have them in our homes and at offices — but a neuroscientist warns that one household staple may be a major threat to our health. Glen Jeffery, a professor of neuroscience at University College London, is sounding the alarm about what he calls a “clear and present public health emergency” that no one seems to be talking about. He has gone so far as to compare the item to asbestos — once widely used in building materials before people realized it can cause issues like mesothelioma and lung cancer. The health threat? Energy-efficient light-emitting diode bulbs, which...