"Unfortunately, we didn't find any survivors," he said after overnight search and rescue attempts.
The freighter left Yeosu on Monday night and was bound for Taiwan, carrying the acid for a logistics company.
The nitric acid on board, though toxic, "would likely be kept in the ship's storage facilities, which have good safety devices", an official said on condition of anonymity.
It was also not likely to cause environmental damage because it easily dilutes, the official said.
The survivor, a 28-year-old sailor from Myanmar, told investigators he watched the vessel sink before he and the other crew members - 12 South Koreans and two from Myanmar, were swept away, Kang said.
Oil spill tanker seized
The news comes as a South Korean government-affiliated pollution agency seized the Hong Kong-registered tanker behind the country's worst oil spill more than two weeks ago.
The move is an attempt to force the vessel's owners to pay for the clean-up of more than 10,000 tonnes of crude oil that leaked from the tanker.
The oil spill occurred when a sea-bound crane mounted on a Samsung Heavy Industries barge punched holes in the tanker on December 7.
|More than 10,000 tonnes of crude oil |
leaked from the Hebei Spirit tanker [AFP]
"We impounded the ship in order to receive compensation for the expenses of controlling the oil spill," said an official at the government-linked Korea Marine Pollution Response Corp.
The South Korean government has yet to release a damage estimate or say how much the clean-up will cost.
Residents say their livelihoods have been ruined because the spill wiped out fisheries and the tourism industry dried up.
Earlier this week, South Korean officials arrested a tugboat captain and barge commander and plan to indict them on negligence and pollution charges early next year, a coast guard official said.
Last week, the coast guard said it was seeking arrest warrants for four people: the captain of the Hebei Spirit tanker, the captains of two tugboats towing the barge and the person responsible for the crane mounted on the barge.
On the advice of prosecutors, the coast guard later decided not to arrest the Hebei Spirit captain and the second tugboat captain.
Both were still being investigated for possible criminal negligence, the coast guard official said.
|Conservationists fear the oil spill will|
cause problems for years [Reuters]
The tugboat captains and barge commander are suspected of taking the crane out in rough waters despite warnings not to do so, local media reported.
A towline between the crane and one of the tugboats severed about 15 minutes before the accident and the tanker did not move out of the way in time, a coast guard report said.
Most of the oil has now been cleared from South Korea's beaches after tens of thousands of volunteers joined the effort.
But conservationists fear the oil that has sunk to the seabed will cause problems for years.