Federal and state authorities have promised a full investigation into Saturday's mishap.
"What happened today is totally inexcusable," tweeted Sen. Brian Schatz. "The whole state was terrified. There needs to be tough and quick accountability and a fixed process."
Rep. Tulsi Gabbard recounted to CNN how people in her state got the phone alert and thought they had 15 minutes to live.
"The reality is that every American needs to understand that if you had gone through what the people of Hawaii just went through, what my family and so many families in Hawaii just went through, you would be angry just like I am," she said.