It sounds like the shape of the dose response curve for chronic low dose radiation is controversial. There's a lack of definitive evidence either way and reasonable arguments in both directions. See https://en.wikipedia.org/wiki/Radiation_hormesis and other independent sources.
This article is making the case in one direction and is biased. I'm not saying it's wrong, but I wouldn't walk away using this as your only source on the topic.
This article is making the case in one direction and is biased. I'm not saying it's wrong, but I wouldn't walk away using this as your only source on the topic.