Well the article title and the HN headline did not specify that.
   In fact after a quick reread the whole article never said what type of radiation.
   What are they talking about? Alpha radiation, Probably not it is mostly harmless unless you eat a radiation source or it gets stuck in your lungs. Betaray imitations? Maybe gamma radiation but wouldn't want to mess with that. UV is ionizing but most people don't think of it.