The toxic red mud flow that has devastated villages in western Hungary, killing four, leaving three missing, and sending 123 people to hospitals with chemical burns, has reached the Moson branch of the Danube river, the Hungarian National Disaster Management Agency reported on Thursday.

Policemen patrol along a street in the flooded village of Kolontar, 150 km (93 miles) west of Budapest October 6, 2010. [Xinhua]

Disaster Management Spokesman Tibor Dobson reported that the pH value of the caustic aluminum industry byproduct had been reduced from pH 13 to pH 9.3, and experts were continuing to lace the water at the meeting of the Raba and Marcal rivers with acetic acid and plaster to reduce the alkaline value still further. A pH value of 7 is neutral, while 9 is equivalent to baking soda. Dobson also said that fish in the river appeared to be surviving.

Millions of gallons of red mud flooded three villages when a retaining wall of a sludge reservoir owned by the Hungarian Aluminum Producing and Trading Company (MAL) gave way on Monday.

The soil in the village of Kolontar was so badly damaged by the deluge, which also contained toxic heavy metals, that the prime minister has suggested moving the entire village.