Japan’s Nuclear Emergency Response Headquarters on Monday finally admitted that the earthquake and tsunami on March 11 resulted to the full meltdown of three reactors in the Fukushima Daiichi nuclear power plant. The statement gave an even bleaker assessment than what they have earlier announced. The assessment was released as a group of expert panel begins its investigation of what actually transpired in nuclear plant that continues to leak radiation to this day.

The agency revealed that Reactors 1, 2, and 3 all experienced total meltdowns. This goes further from the assessment gave by the plant’s owner, Tokyo Electric Power Co., which last month painted a possible scenario that tells the nuclear fuel rods in both Reactors 2 and 3 may have been damaged but did not experience total meltdown. Nevertheless, everybody seems to agree that the fuel rods in Reactor 1 melted in the first 16 hours after the tsunami.

The revision is set to put Japan as a recipient of further criticism for their slow release of information regarding the crisis. Japan’s Nuclear and Industrial Safety Agency (Nisa) estimated 770,000 terabecquerels have leaked to the atmosphere. Even if that translates to just 15% of what was released in Chernobyl, Ukraine in 1986, it suggests that the contamination caused by the accident to surrounding areas is far more damaging than earlier announced. Worse, it took nearly three months before the public knew of the actual extent of the nuclear meltdown.

The UN’s atomic watchdog International Atomic Energy Agency (IAEA) released last week their preliminary report pertaining to the Fukushima nuclear crisis. They observed that Japan clearly underestimated the hazard that tsunamis could possibly pose to nuclear plants. In their report, they urged Japan to form an independent regulatory board to make sure their nuclear facilities are well equipped in the event of natural disasters like tsunamis, which have been known to historically frequent the country.

The report details some of the procedural and structural weaknesses that may have contributed to the meltdown in the Fukushima plant, which is just over 200 kilometers north of Tokyo. The agency also urged nuclear designers and operators to make proper evaluation and protective measures to prepare against the risks of natural hazards. They also added that these measures and assessment methodologies must be periodically updated.

Despite the announcement, plans have not changed on how to stabilize the Fukushima Daiichi plant, according to the Nuclear Emergency Response Headquarters. News has spread that Japanese Naoto Kan will be stepping down after calls for him to resign due to the mishandling of the crisis gained steam.

Kan’s DPJ currently holds majority in the Diet, the country’s lower house of parliament. Leaders of the majority are now contemplating a grand coalition government with the opposition LDP as soon as Kan steps down from office which is believed to happen this month.