The nuclear fallout from the 9.0-magnitude earthquake and ensuing tsunami that rocked Japan on Friday continues to escalate.  After a third reactor explosion occurred early Tuesday morning at the Fukushima nuclear power plant, a fourth reactor started on fire causing more radioactive material to be released.

Radioactive material has now leaked from four reactors, leading the government to issue a warning to the remaining 140,000 people in the surrounding area to stay indoors and not open any windows or vents.  70,000 people have already been evacuated from within a 20 kilometer radius from the plant.

The latest radiation readings from the Fukushima plant show levels 100 times greater than normal.  However, experts say that although these numbers are worrying in regard to prolonged exposure, they are far from fatal.  Nevertheless, Chief Cabinet Secretary Yukio Edano made it clear the situation is hazardous:  "These are figures that potentially affect health.  There is no mistake about that."

He also said the radiation levels would be significantly lower in areas miles away from the northeastern state of Fukushima.  Tokyo reported slightly higher levels of radiation that normal on Tuesday.  This is the worst nuclear disaster in Japan since the Atomic bombs were dropped in World War II, and the worst in the world since the Chernobyl catastrophe in Ukraine in 1986.

Industry experts have been quick to explain the Fukushima situation has not reached a state close to the Chernobyl disaster.  Donald Olander, professor emeritus of nuclear engineering at University of California, Berkeley.  Olander says the Japanese government is taking a smart, cautious approach with the evacuations.  In his opinion, the radiation levels have still not reached critical levels for human health, and they are nowhere near Chernobyl.

With mounting fears from the public about a nuclear meltdown, the United Nations nuclear watchdog, the International Atomic Energy Agency said there is no indication at the given time that a nuclear meltdown of the Fukushima nuclear facility.  "We have no indication of fuel that is currently melting at this point," said James Lyons, director of the Safety at Nuclear Installations division.

Nevertheless, the appearance of a worsening nuclear situation, coupled with the incredible infrastructural damage caused by the earthquake, has led the Japanese stock exchange to experience the second-largest one-day fall in its history

The exchange, known as the Nikkei, dropped as much as 14% during Tuesday's trading session.  It recovered in the afternoon to close at 8,605.15 -- a drop of 10.55%.  On Monday, the market's main index dropped 6.2%.  It is estimated that between the two-day sell off, US$500 billion has been liquidated from the market.