The hotel is located at 100 Woodland Pond Dr. on the SAS campus, near Umstead State Park.
Hotel workers could be seen running through hotel parking lot as guests left the building.
Multiple fire engines and ambulances were staged at the scene, including Wake County EMS Major Operations Support.
A spokesperson for the Town of Cary said workers were using an epoxy on a floor in the basement, when fumes became too strong.
At least one person was treated for exposure.