Sendai, Japan (CNN) — Japan worked against the clock on Tuesday to avert nuclear fallout, as relief workers cranked up their searches for survivors of last week’s massive and deadly earthquake and tsunami.
The Asian economic powerhouse reeled as the death toll spiked to 3,373 and the stock market plummeted for a second straight day — a 10 percent drop this time — during what Japanese Prime Minister Naoto Kan said was the country’s worst crisis since World War II — when American jets dropped nuclear weapons on Hiroshima and Nagasaki.
Shell-shocked people huddled in cramped shelters, grieved over lost loved ones, and worried about missing next of kin lost throughout villages and towns inundated by the powerful tsunami waves spawned by the 9.0 magnitude quake off the east coast of Honshu on Friday.
“The scale of this event has taken everyone by surprise,” said Patrick Fuller, Red Cross spokesman. “It’s stretched resources to the max.”
Fears of radioactive exposure gripped the country as workers tackled quake-crippled cooling systems at the Fukushima Daiichi nuclear plant in northeastern Japan and coped with fires and explosions there.
In the latest incidents, a fire broke out at the No. 4 reactor building and was later extinguished, and an explosion occurred at the No. 2 reactor.
High temperatures inside the building that houses the plant’s No. 4 reactor may have caused fuel rods sitting in a pool to ignite or explode, the plant’s owner said.
Radiation level readings spiked at the building gate during the fire, but went down after the blaze was extinguished, with Chief Cabinet Secretary Yukio Edano saying amounts returned to a level that would not cause “harm to human health.”
David Brenner, director of the Center for Radiological Research at Columbia University, said he thinks “at this point in time there’s no real evidence that there are health risks to the general population.”
For example, radiation levels in Tokyo were twice the usual level on Tuesday but they were too negligible to pose a health threat, officials said.
But Japanese authorities couldn’t rule out the specter of greater radiation dangers down the road.
For the first time since the quake crippled cooling systems at the Daiichi reactors on Friday and blasts occurred at two reactors Saturday and Monday, Edano said radiation levels at the plant had increased to “levels that can impact human health.”
Edano said Tuesday he could not rule out the possibility of a meltdown at the troubled reactors. While sea water was being pumped into the reactors in an effort to prevent further damage, “it cannot necessarily be called a stable situation,” he said.
The plant’s owners have taken precautions to protect the people in Fukushima Prefecture, where the reactors sit. The plants are 138 miles (223 kilometers) from Tokyo.
They evacuated all but about 50 workers from the facility and urged people within 30 kilometers (18.6 miles) of the plant to remain indoors. The government imposed a no-fly zone over the 30-kilometer radius “because of detected radiation after explosions” there, the country’s transportation ministry said.
Analysts also have their eyes on reactors No. 5 and 6 at the plant, Edano said, where cooling systems were “not functioning well” and the temperature had dropped slightly Tuesday.
For many across Japan, calming jittery nerves is becoming increasingly difficult as the situation at the damaged facility looks increasingly dire with each passing day.
“I think from a sanity standpoint I’m trying to side with the cool-headed point of view because I don’t want to think about the possibly of a full-blown meltdown,” said Osaki resident Tyler Martin.
“So far the winds are blowing north/northeast, so if a lot of radiation leaks, Tokyo shouldn’t get a lot of the exposure,” said Robert F. Mendel, who lives in suburban Tokyo.
“Of course, if the winds change, that’s a different story. We’ve been advised to wear long sleeves, a cap, a surgical mask to reduce the amount of exposure — that is, cover as much skin as possible.”
At least 6,746 people were still missing Tuesday, the National Police Agency said, and 1,987 were injured.
Public broadcaster NHK reported that 450,000 people were living in shelters, and many schools had turned into emergency shelters.
Across the country, emergency workers from foreign governments and international aid groups continued Tuesday to scour tangled and displaced piles of debris, searching for survivors. Ninety-one countries and regions and six international organizations have offered assistance, according to the Japanese foreign affairs ministry.
In the area of Sendai, the capital of Miyagi Prefecture, several tractor-trailers with cars on top had flipped over. Personal belongings — a child’s doll, an empty shoe, wedding photos covered in mud — lay in heaps where houses once stood.
At a shelter in the city, a shell-shocked man who fled the tsunami would not let go of his 3-week-old infant. “I have to protect my children. I have to protect my children,” he said.
Another survivor wiped away tears after someone she barely knew gave her food and water.
Members of the Japanese army paddled across heavily-flooded streets in Ishinomaki to rescue several people at an office building. The group, was huddled on a ramp surrounded by water, had been stranded for three days.
Cold weather has increased the hardship for disaster victims and rescuers. Rescuers report that some victims have been exposed to cold weather and water, in some cases for days.
Conditions are expected to worsen, with temperatures forecast to drop below freezing by Wednesday across portions of the earthquake zone, accompanied by snow, heavy rain and the threat of mudslides.
Already in Sendai, cold rain and sleet fell on the decimated city Tuesday, and snow fell in parts of northeastern Japan.
Economic and power problems also loomed.
With the imperiled Fukushima plant offline, Tokyo Electric Power said it was expecting a shortfall of about 25 percent capacity, which necessitated blackouts. Up to 45 million people will be affected by the rolling outages, which will last until April 8.
Experts predict that the earthquake and tsunami will rank among the costliest natural disasters on record.
Japan’s central bank announced plans Monday to inject 15 trillion yen ($186 billion) into the economy to reassure global investors of the stability of Japanese financial markets and banks.
Still, Japanese stocks closed down 10.55 % Tuesday — the third steepest percentage fall in the Nikkei’s history.
That was on top of a 6.2% drop Monday, the first full trading day after the quake, which also marked the largest single-day fall since September 2008 after the collapse of Lehman Brothers during the financial crisis.
Friday’s quake was the strongest in recorded history to hit Japan, according to U.S. Geological Survey records that date to 1900. The USGS revised the magnitude of the quake from 8.9 to 9.0 on Monday.