The latest admissions by Tokyo Electric Power Co. (TEPCO) have reignited fears about nuclear safety in a country that relies on atomic power for one-third of its electricity but has faced repeated cover-ups of past accidents by atomic power utilities.
I believe that nuclear power plants can only be operated with the trust of the people, Prime Minister Shinzo Abe told reporters in Tokyo, about 250 km (155 miles) south-east of Niigata prefecture, where the quake struck on Monday morning.
For this, if something happens they need to report on it thoroughly and quickly. We need to get them to strictly reflect on this incident, Abe added.
A small fire in a transformer at TEPCO's Kashiwazaki-Kariwa nuclear power plant that occurred when the 6.8 magnitude quake struck at 10.13 a.m. (0113 GMT) on Monday, was extinguished a few hours later.
But NHK television said TEPCO workers had tried to douse the fire with water before fire fighters arrived and put it out with chemicals.
TEPCO had initially said the earthquake had not caused any leaks, but it revealed on Monday night that 1,200 liters of radioactive water had sloshed into the sea from its Kashiwazaki-Kariwa plant in Niigata.
I think that the report on the leak of radioactive materials was very slow and in addition, the action to put out the fire was slow, Sanae Takaichi, the minister in charge of science and technology, told reporters. She urged the utility to come up with a plan to prevent a recurrence.
NUCLEAR WASTE DRUMS TOPPLED
Then on Tuesday, TEPCO officials confirmed a media report that said about 100 drums containing nuclear waste at a warehouse had fallen over and several lost their lids.
Only about half of 22,000 drums had been inspected so far, Nagao Suzuki, a TEPCO nuclear operations official, told a news conference in Tokyo. A TEPCO spokesman later said there was no impact on the environment or people.
Also on Tuesday, the company said a small amount of radioactive materials, including cobalt-60 and chromium-51, had been emitted into the atmosphere.
Trade ministry officials said the amounts were too small to pose an environmental threat, but that checks were being made at other units at the plant for possible leaks.
TEPCO had acknowledged on Monday that the quake was stronger than its reactors had been designed to withstand.
It was unclear on Tuesday when TEPCO's power units could restart.
Media as well as local residents urged the nuclear industry to take heed of the threat and make sure reactors were safe.
When you have something like this, it's scary, said retired taxi driver Tomiji Okura, 72, in Kashiwazaki, a city of about 95,000 whose economy relies heavily on the nuclear industry along with fishing. I want them to be made safe.
NINE KILLED, HOMES DESTROYED
Nine elderly people were killed by the quake, and one person was missing, a Niigata prefecture official said.
Nearly 800 homes were destroyed or damaged in Niigata alone and much of the water, gas and electricity supplies cut by the quake had yet to be restored on Tuesday.
About 9,000 people were set to spend a second night in schools and other make-shift evacuation centers.
I can't sleep here because I can't feel at ease, because this is different from home. When I start thinking about what's going to happen, it's even harder to sleep, said 73-year-old retiree Katsuro Iida, 73, taking shelter at a primary school.
Worries were mounting about the health of evacuees, many of whom are elderly.
Streets in Kashiwazaki were lined with damaged or collapsed houses, mostly wooden structures with heavy tile roofs, and fresh water was trucked in.
Helmeted soldiers in camouflage uniforms made rice balls to hand out at evacuation centers, where crowds huddled sitting on tatami straw mats with blankets and a few belongings.
Japan is one of the world's most earthquake-prone countries, and for many Niigata residents, there was a tragic sense of deja vu.
The prefecture was hit in October 2004 by a quake, also with a magnitude of 6.8, that killed 65 people and injured more than 3,000. It was the deadliest quake in Japan since a magnitude 7.3 tremor hit Kobe city in 1995, killing more than 6,400.
(Additional reporting by Isabel Reynolds, Osamu Tsukimori, Chikafuji Hodo, Noriyuki Hirata, Elaine Lies and Linda Sieg)