Work resumes at Japan's troubled nuclear power plant

The operator of a stricken nuclear power station resumed work Thursday to restore power and key cooling functions after it was disrupted by dark smoke from a reactor building on Wednesday, dpa reported.

Workers at reactor buildings 3 and 4 as well as those manning fire trucks had to leave the site after the smoke was seen from the building of overheating reactor 3 at Fukushima 1 nuclear power plant, which was damaged by the March 11 earthquake and resulting tsunami.

The government's nuclear safety commission confirmed that the smoke stopped early Thursday, Kyodo News reported. The cause of the smoke was not known, the commission said.

External power reached all six reactors at the plant late Tuesday and the operator, Tokyo Electric Power Co, was struggling to restore power and revive cooling systems and other key functions.

As fear of radioactive contamination has spread, the government has launched monitoring of the radiation levels in soil, seawater and air around the plant to look into the extent of pollution and its impact on agricultural and fishery products.

In Iitate village, Fukushima, 40 kilometres north-west of the stricken plant, soil contamination was reported. The Science Ministry found radioactive caesium at levels of 160,000 becquerels, 1,600 times the usual level, public broadcaster NHK reported Wednesday.

In Tokyo, 240 kilometres south-west of the plant, the metropolitan government issued a health warning Wednesday that infants should not drink tap water.