JAPAN’S NUCLEAR SAFETY agency has raised the severity of the alert for the crisis-stricken country from a Level 4 to a Level 5, brining it on a par with the Three Mile Island nuclear incident in the USA in 1979.

The International Nuclear Event Scale defines Level 4 as “an accident with local consequences”, while Level 5 indicates “an accident with wider consequences”. The highest level on the scale is Level 7.

The International Atomic Energy Association says that a Level 5 situation will result in “a limited release of radioactive material” and is likely to require the “implementation of some planned countermeasures”. It also indicates that there will be several deaths from radiation.

A Level 5 is typically caused by an incident that causes “severe damage” to a reactor core, and which results in the release of large quantities of radioactive material, reports the Press Association.

The 1986 Chernobyl accident in Ukraine was ranked as a Level 7. A least 37 people died due to radiation as a result of the incident, and the long-term affects included birth defects and increased cancer rates.