Engaget's Nilay Patel reports that "mice injected with certain lengths of nanotubes developed lung problems similar to those caused by asbestos."
When nano materials were first excitedly proposed several years ago, they were predicted to solve all sorts of mankind's problems -- kind of like embryonic stem cells are to be our salvation from the inconvenience of disease and death.
At the time, I worried that extremely small particles would become a health hazard. I had the experience of working in very dusty conditions (potato farming) and in high pollution areas (aluminum smelting). I knew about the asbestos crisis in Quebec mining towns.
Really small particles are nasty for the breathing parts of our bodies.
I'm glad to read that science is starting to back up my hypothesis.