The move, during a shift change, set off panic.
The Federal Communications Commission sets rules for wireless emergency alerts sent by local, state or federal officials to warn of the threat of hurricanes, wildfires, flash flooding and to announce searches for missing children.
It took more than a half hour for people to find out the threat was not real. That delay is angering some lawmakers.
“Yes, it was unacceptable that it went out in the first place. But the fact that it took so long for them to put out that second message, to calm people, to allay their fears, that this was a mistake,” U.S. Rep. Tulsi Gabbard said.
President Donald Trump is pledging federal help in the investigation.
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