The head of the U.S. Department of Energy said today that the nuclear disaster unfolding in Japan could be worse than the 1979 Three Mile Island accident in Pennsylvania that dampened Americans' view of nuclear power plants for decades to come.
"Events unfolding in the Japan incidents appear to be more serious than Three Mile Island. To what extent, we don't know that. They are unfolding hour by hour," Energy Secretary Steven Chu said earlier today at the hearing.
Chu's assessment is in line with views expressed by many experts, some of whom even believe the Japan crisis could be worse than the 1986 Chernobyl nuclear disaster in Ukraine that left hundreds sick and killed several from radiation.
The United States has deployed thousands of military and civilian staff to assist the Japanese in dealing with the aftermath of the earthquake and the resulting tsunami, which has killed thousands.
To date there have been 113 helicopter missions and 125 fixed wing missions. More than 129,000 pounds of water and 4,200 pounds of food have been delivered .
The Department of Energy and Nuclear Regulatory Commission has sent teams of U.S. experts to assess the nuclear situation.
U.S. aid to Japan has reached nearly $5.9 million, with total planned assistance amounting to $8 million. USAID says the primary humanitarian needs on the ground remain food, safe drinking water, blankets, medical supplies, fuel, and sanitation infrastructure.
ABC News' Huma Khan and Luis Martinez contributed to this report.