It is 'imperative' that the public be informed about these dangers. = It is 'imperative' to inform the public about these dangers.
“Go” and “buy” are 'imperatives' in the sentence “Please go to the store and buy some milk.”
She considers it a moral 'imperative' to help people in need.
(..) Hide yourself below, Harry. Don't speak or be seen by anybody without my permission. Whatever happens, it's imperative you stay below. Harry, do as I say. Trust me. Trust me. Good evening, Draco. What brings you here (..)2009 Harry Potter and the Half-Blood Prince