Is low-dose radiation harmful?

At high doses radiation is clearly harmful — but at the low doses around nuclear power, near natural background, the science is genuinely unsettled, and that's important to know. Regulation uses the cautious Linear No-Threshold (LNT) model, which assumes every tiny dose carries proportional risk. A substantial body of research questions this, suggesting low doses are essentially harmless.

This is the clearest contested question on the site, so we won't overclaim: the truth likely lies short of LNT's pessimism. The optimistic and well-supported takeaway is that the health risks of low-dose radiation have very probably been overstated for decades — which means much of the fear, and cost, attached to nuclear has been overstated too.