Honestly, i think one of the mistakes in the reporting is using the Sievert system when talking about contamination, because most people have no bloody clue what it means, and it is not readilly explained. Hell, when i have seen it explained by people who work with radioactive materials every day, even they say there is confusuion about the system within the industry, where a lot of the workers still use Rads and REM because it's easier to use.
Just go with Rads, most people understand the Milli-Rad system.
But maybe that's exactly the point, the less people understand it, the easier it is to scare them.