Fukushima explosion unlikely to pose danger - nuclear expert:

The explosion at the Fukushima 1 nuclear power plant was likely to be caused by burning hydrogen and will not necessarily lead to a radiation leak, a representative of the London-based World Nuclear Association said.

According to Ian Hore-Lacy, the head of communications for the World Nuclear Association, if it was hydrogen that exploded it must have turned into smoke and there is no danger of a radiation leak.

Smoke was seen coming from the plant in the wake of the explosion which followed a powerful underground tremor, Tokyo Electric Power reports.

Four workers were injured.

In the meantime, Chief Cabinet Secretary Yukio Edano says there was no explosion at the Fukushima 1 number one reactor.