The South Korean government on Monday said it has decided to designate areas affected by a toxic chemical leak in the southeastern city of Gumi as a "special disaster" zone in the face of the intensifying damage.

Some eight tons of hydrofluoric acid leaked from chemical maker Hube Global's plant in Gumi after an explosion on 27 September have caused widespread damage to crops and livestock.

The explosion killed five people. Since then more than 3,000 residents have received medical treatment for nausea and other ailments after inhaling toxic fumes from the spilled acid, according to local media reports. "The need for a special action at national level has been recognized as the government's inspection conducted between Oct. 5 and 7 showed that the damage is presumed to be too severe for the local government to handle on its own," the prime minister's office said in a statement.

The move will allow residents to be eligible for financial aid, tax cuts and compensation.

The damage reported by companies in the Gumi National Industrial Complex is estimated at about 17.7 billion won (15.9 million U.S. dollars), according to Yonhap news agency.

The leak also withered more than 200 hectares of farmland and affected some 3,200 livestock.

About 300 villagers have been evacuated to temporary shelters amid concern over health risks.