Factual error: In episode 17 there are some scenes showing sick 4400s all around the world. One of them is being carried into an ambulance car in Frankfurt, Germany. The ambulance car's number plate begins with the letters FM meaning Frankfurt am Main. The correct abbreviation for Frankfurt am Main on German number plates is F - not FM.
Factual error: Missiles are launched at comet, then after impacting the comet it shows the comet passing the moon. Terrestrial missiles do not have the fuel to reach an object that far in space. The missiles were shown with flame and exhaust indicating they were still in the atmosphere. At the time they stated China launched its missiles the object had a time to impact of 28 minutes and speed of 3000 Km per second. Apollo 11 was going faster and it took 3 days to get to the moon. At 10 seconds to impact the missiles shown were still in the Earth's atmosphere. (00:00:07)
Factual error: The co-ordinates of the comet's landing point are given as 47 north longitude and 122 west latitude, thus giving the latitude and longitude the wrong way round. (00:10:10)
Factual error: When Lily and Richard are talking in a coffee shop, a TransLink trolley passes by outside. A TransLink is never seen in Seattle, but it is seen in Vancouver, where the show is filmed.