UNITED NATIONS -- As the crisis over Japan's disaster-stricken nuclear reactor deepens, authorities there are confirming cases of radiation poisoning and injuries at the Fukushima No. 1 power plant, U.N. officials said today.

Japan's chief Cabinet secretary has told the International Atomic Energy Agency (IAEA) that 21 plant workers and emergency responders were injured by hydrogen explosions at the plant, U.N. officials said. Most of the injured workers required hospitalization, including two who came down with sudden illnesses, they said.

Two more people are reported missing at the site, raising concerns about the wellbeing of Japanese military, firefighters and Tokyo Electric Power Co. (TEPCO) employees who are battling to prevent a full reactor core meltdown (ClimateWire, March 17).

The IAEA has also been told that at least 20 people have suffered radiation exposures. Seventeen of those cases are said to have been minor, mainly involving radioactive material that was deposited on workers' faces and quickly washed off, requiring no hospital visits.

But at least one TEPCO worker suffered "significant exposure" and was taken to an offsite decontamination center, the U.N. agency reported.

Two Japanese policemen required decontamination and an undisclosed number of firemen are "under investigation" for possible radiation poisoning, the agency said.

Reports that the nuclear crisis at the Fukushima plant may be far worse than what TEPCO or the Japanese government had said before prompted IAEA Director General Yukiya Amano to plan a departure later today to his native land to meet officials involved in the response and see how his agency can help.

Amano told reporters in Vienna that he intends to help facilitate IAEA assistance, but he also said he wants to ensure that his agency obtains better and timelier information on developments in Japan.

Several IAEA experts will accompany Amano on the Japan trip. He said he would request an emergency meeting of the IAEA board of governors upon his return to the agency's Austrian headquarters.

Data trickling out of the Fukushima plant to the IAEA have raised alarms at the agency, painting a picture that Amano said was "very serious" and in need of a deeper on-the-ground IAEA-led investigation.

Japan provided temperature readings on the spent fuel pools in various units at the damaged plant that showed most gauges reading more than double the normal levels, the agency said. Temperatures at the Unit 4 spent fuel pool were 84 degrees Celsius (183 degrees Fahrenheit) over the past few days. The safe limit is 25 degrees Celsius (77 degrees Fahrenheit).

Also yesterday U.N. Secretary-General Ban Ki-moon spoke with Japanese Premier Naoto Kan by phone to discuss the tsunami aftermath and the ongoing nuclear power plant crisis. U.N. press officers said Ban told the Japanese leader that he "remains very concerned while appreciating the government of Japan's efforts to contain the risk to the population."

Earlier this week, the U.N. Office for the Coordination of Humanitarian Affairs dispatched an emergency response team to assist Japan with post-disaster relief efforts. IAEA experts are also on the ground conducting environmental monitoring of the zone surrounding the damaged nuclear power plants.

The Japanese government now says that as many as 15,000 people could have perished from the March 11 earthquake and tsunami that hit the northeast part of the main island. Around 6,000 are confirmed dead but about 9,000 more are said to be missing.