Tokyo ( CNN ) -- A low water level in a reactor building at the damaged Fukushima Daiichi nuclear power plant in Japan may have exposed fuel rods and caused them to melt , the owner of the facility said Thursday . Tokyo Electric Power Co. blamed the incident on a faulty gauge that monitors the water level in the pressure vessel in the No . 1 reactor building . `` I would say at this point that the situation is not dangerous , '' said Mujid Kazimi , a professor of nuclear engineering and mechanical engineering at the Massachusetts Institute of Technology . The Nuclear Energy Institute had a similar response to the new details released by Tokyo Electric . `` This is in no way alarming , '' said Tom Kauffman , senior media relations manager at the Washington-based institute . `` It was anticipated that there was fuel damage in reactors 1 , 2 and 3 . This is confirmation , '' he said . `` It 's a situation that 's going to develop over time , '' with details continuing to emerge as nuclear plant workers gain more access to the reactors , Kauffman added . `` This is going to evolve over months , maybe many months . '' Once the faulty gauge was reset , workers discovered Thursday that the water level had dropped more than 3 feet ( 1 meter ) below the fuel rods , which need to be cooled by water to keep them from melting . Japan 's Nuclear and Industrial Safety Agency said there 's a high possibility that the fuel rods have melted and are now being cooled by water in the bottom of the pressure vessel . The company said it suspects there is a leak in the pressure vessel , since the water level was low despite the company pouring 150 tons of water a day on the No . 1 reactor to cool it . A March 11 earthquake and tsunami knocked out cooling systems at Fukushima Daiichi , causing the three operating reactors to overheat . That compounded a natural disaster by spewing vast quantities of radioactive material into the atmosphere . Workers have been able to install air filters inside the No . 1 reactor building to contain radioactive particles and have begun filling the primary containment shell around the reactor core with water in an attempt to draw heat off the core . The plan is to recirculate that water through a heat exchanger to cool it , said Yoshikazu Nagai , a spokesman for Tokyo Electric . Similar plans are being considered for unit 2 , which also is thought to be leaking radioactive water , and unit 3 , where engineers noted a disturbing rise in the reactor 's temperature readings last week , Nagai told CNN . `` First we have to tackle unit No . 1 , and we need to see if we can succeed , '' he said . Meanwhile , equipment that will be used to decontaminate water pooling in the plant 's basements is expected to arrive by mid-May . Tens of thousands of tons of radioactive water have flooded the basements where the cooling systems were housed , making it impossible for workers get into the facilities . At this point , `` The danger is more with the workers who deal with ( the leak ) than the public , '' Kazimi said . Decontaminating the water pooling in the plant 's basements is feasible , as long as the water stays contained , he added . To limit further possible spread of contamination beyond the evacuation zone around the nuclear plant , Japan 's Ministry of Agriculture , Forest and Fisheries on Thursday decided to euthanize livestock in the zone . There is a no-entry zone within a 20-kilometer radius of Fukushima Daiichi . `` It is yet to be determined how and when they do ( the euthanizing ) , but we would cull livestock with the most painless way with permission of the owners of them , '' a spokesman for the Fukushima prefectural government said . It 's unclear how many livestock survive in the zone , but before the disaster there were approximately 3,500 cows , 30,000 pigs , 440,000 chickens , 100 horses and an unknown number of sheep . With their owners having evacuated , the livestock have been left to fend for themselves . CNN 's Kyung Lah , Noriaki Kawai and Yoko Wakatsuki in Tokyo contributed to this report .
NEW : Government decides to euthanize livestock in no - entry zone . NEW : No need for alarm among the public , but nuclear workers face risks , government says . Tokyo Electric Power Company blames the accident on a faulty gauge . A new gas leak is suspected at Fukushima Daiichi Plant No . 1 .