Chernobyl was projected to kill millions. The top epidemiologists in the world projected in the most realistic scenarios that the death toll would have been in the millions prior to the quarantines. Both could have been prevented if people knew the truth well in advance of the crisis.
Call it hyperbole, but the Spanish Flu killed millions because the public was not told the truth soon enough. We were likewise told this was nothing to worry about for months, and now we have ~30%-50% of the US quarantined.