Documents released by U.S. nuclear regulators shows officials were operating in a “very hectic” environment in the first days of last year's Japanese nuclear crisis.

The U.S. Nuclear Regulatory Agency released more than 3,000 pages of transcripts Tuesday showing the agency's response to the Fukushima nuclear plant disaster in March 2011. NRC Chairman Gregory Jaczko told reporters officials were forced to rely on information from local officials and Japanese news media, much of it inaccurate.

At one point, Jaczko publicly stated that a pool in the crippled reactor used to cool spent nuclear fuel rods was dry, increasing the chances of more radiation leaking into the air. But he was later informed his initial information was incorrect.

NRC officials also struggled over an eventual evacuation recommendation for U.S. citizens living within an 80-kilometer radius of the plant.

The March 11,2011 earthquake and tsunami damaged the cooling units at the Fukushima plant, leading to the world's worst nuclear disaster since the 1986 Chernobyl accident in Ukraine.