Story highlights An explosion at a chemical plant has left thousands of people with health complaints

It has affected hundreds of acres of farmland and thousands of livestock

A local farmer says his crops of grapes and rice have been ruined

The national government has declared a "special disaster zone" in the area

October is supposed to be the busiest month of the year for Lim Chae-ho's vineyards and rice fields in the southern part of South Korea.

In a normal year, the 50-year-old farmer would be in the midst of harvesting the crops he had spent months cultivating. But a toxic leak from an explosion at a chemical plant in the nearby city of Gumi two weeks ago has left him empty handed.

"Grapes and rice crops are withered and cannot be sold," Lim said over the phone.

"All our neighbors are affected," he said. "My neighbor's 60 cows are drooling and their noses are running with snot and blood. They are refusing to eat."

Thousands of people in the area have been affected by the blast at the chemical factory on September 27, which killed 5 people and injured 18 others at the time.

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The exact cause of the explosion, which involved 8 tons of hydrofluoric acid, is still being investigated, according to authorities. But the blast spread toxic vapor from the acid -- which is used for tasks like metal cleaning and rust removal -- across the surrounding area.

In the ensuing days, about 3,200 people have visited hospitals seeking treatment for ailments related to the leak, the city government said Sunday.

The national government on Monday declared a "special disaster zone" around the plant. Around 300 people are being relocated to safer areas.

The health problems people are suffering from include headaches, nausea, sore throats and severe coughs, according to Jung Soo-geun, an official at a local environmental group, Daegu Environmental Movement Association.

He said people in the area were concerned about the possible long-term effects of the toxic vapor on their bodies.

"I visited the site several times and ended up getting a sore throat as well," Jung said.

The chemical leak has affected at least 3,200 livestock, damaged more than 1,000 vehicles and caused about $16 million worth of damage to companies in the area, according to the city government. It has spread across about 230 hectares (570 acres) of farmland, the equivalent of roughly 430 American football fields.

But the chemicals have not contaminated the local water system, the city government said.

To help deal with the situation, the national government has said it will offer financing for recovery efforts by local authorities. It will also provide compensation and insurance payments, as well as tax cuts, to residents and companies affected by the disaster.