As reported by CBC, Bruce Power, which leases and operates 6 atomic reactors in Kincardine, Ontario, has exposed more than 200 of its own workers, as well as contractors, to ultra-hazardous alpha radioactivity. The workers were not wearing respiratory protection as pipes contaminated with alpha-emitting radioactive particles were ground through during steam generator replacement activities.
The risk is that a minute quantity of alpha radioactivity, inhaled into the lung, will cause latent lung cancer. The latency period can be measured in years, or even decades. Hence, nuclear authorities' oft-invoked euphemism, "no immediate danger," as has been invoked in this particular disaster as well.
The phrase featured so prominently during the Three Mile Island meltdown that Rosalie Bertell used it as the title for her post-TMI exposé. But she added a loaded question mark on the end!