Denver is one of nine potential sites for the $500 million plant.
New Jersey has also been mentioned as a potential site.
But in private, officials have said they eliminated other potential sites.
Two other potential sites in America were rejected for very different reasons.
The problems had started the day they began looking at potential sites.
Warning signs are also found on other potential dangerous sites.
The company claims to have identified 500 potential sites for future stores.
Another 32 potential sites noted by the city have buildings on them.
New York's effort to win the project failed in part because the administration proposed three potential sites rather than one.
Eleven of the 15 potential sites are within that area.