HUNGARIAN OFFICIALS HAVE announced that the threat to the river Danube posed by a toxic sludge spill in Hungary has declined, reports the BBC.

The news comes as the death toll from the chemical disaster reached five, following the death one of the injured in hospital on Friday.

Three people are still missing after Monday’s accident, which occurred when the reservoir at an alumina plant in Ajka, western Hungary, burst and sent approximately one million cubic metres of chemical waste tearing through the nearby villages.

Fears that the waste could pollute the Danube sparked a major effort by disaster crews to reduce the alkaline content in the sludge, to render it harmless to the ecosystem.

The Danube is a major 2,850 kilometre-long European waterway, which originates in Germany. The effects of its contamination would be grave as the river flows from Hungary to Croatia, Serbia, Romania, Bulgaria, Ukraine and Moldova before emptying into the Black Sea.

Despite the threat of pollution to the Danube declining, fresh concerns have arisen. It has emerged that, as expected warmer weather arrives, the drying mud could spread toxic particles through the air.

Hungary has asked the EU for urgent help in dealing with the disaster.

A spokesman for Greenpeace International, Herwit Schuster, said the spill was “one of the top three environmental disasters in Europe in the last 20 or 30 years”.