It's being called a suicide mission as helicopter pilots drop water on the stricken Japanese nuclear plant in a desperate bid to prevent catastrophe.
On Good Morning America, physicist Michio Kaku told George Stephanopoulos, "It will be a suicide mission to go in. The radiation levels are already lethal right now. You are committing suicide to spend large amounts of time there."
"Even those helicopter pilots going above," said Stephanopoulos.
"That's right," said Kaku.
Their sacrifice is more tragic because it may be too little, too late. One expert described the helicopter mission as "using a squirt gun on a forest fire."
Now, the families of the men risking their lives at the plant are sharing their anguish for the first time.
One teenager tweeted: "My dad went to the nuclear plant. I never heard my mother cry so hard. Please dad, come back alive."
Another e-mailed: "My father says he has accepted his fate. Much like a death sentence."
And there is growing frustration with Japan's handling of the crisis. One U.S. official complains that Japanese authorities are "Frozen in place...it's not working."
INSIDE EDITION's Diane McInerney spoke with CBS News correspondent Charlie D'Agata, who was close to the disaster zone.
"People are scared, they're frustrated and increasingly angry, and there doesn't seem to be any relief on the horizon," said D'Agata.
McInerney asked, "Is the cultural reluctance to give bad news part of the problem here?"
"I think you maybe hit the nail on the head. Nobody wants to hear bad news. Nobody wants to deliver bad news. But it doesn't work when you have such a critical moment," said D'Agata.