Corrosive chemical leak at Vietnam alumina plant 'under control'

By Thien Nhan   August 4, 2016 | 08:25 pm PT
It would be rash to blame the leak for mass fish deaths, authorities say.

A leak at an alumina plant in the Central Highlands province of Dak Nong Province is under total control, Ngo Xuan Loc, chairman of the provincial People’s Committee, said at a press conference on Thursday.

Local people who waded into Dak Cao Stream to remove dead fish and experienced itchiness and a burning sensation on their skin are recovering well, Loc said.

At least 13 people reportedly came out in rashes after wading in the stream close to the alumina plant.

The provincial official, however, said it would be rash to assume that the mass fish deaths in Dak Cao Stream and the allergic reactions some locals experienced are attributable to the sodium hydroxide leak.

Authorities will wait for test results of samples taken from the stream and the dead fish before making any official conclusion, said Loc.

Initial tests seem to confirm that the water in Dak Cao is normal. Provincial environmental officials said that high levels of iron and chromium in the stream that are beyond the permissible limits are due to “natural factors”.

They said that deposits of bauxite in the area along with the steep terrain and heavy rainfall were to blame.


A local man's skin turned red, sore and swollen after he waded into Dak Cao Stream. Photo by Thien Nhan.

The incident occurred on July 23 when a pipeline transporting the corrosive chemical sodium hydroxide to the production area at the Nhan Co alumina plant suddenly burst.

Some 9.6 cubic meters of sodium hydroxide leaked out, posing serious environmental threats to nearby residents.

The leaked chemical has reportedly penetrated an area of 600 square meters, and some of it has been flowing into a stream, state media reported.

The management board described the incident in a report as "unprecedented" and "uncontrollable".

On July 23 and 24, local people reported that the stream had turned abnormally opaque and a large number of fish were dead.


Local people have blamed the chemical leak from the Nhan Co alumina plant for poisoning Dak Cao Stream. Photo by Thien Nhan.

Local authorities said they are taking the incident seriously and have stepped up efforts to keep the leak under control and prevent a similar spill from occurring in the future.

The pumping system for the sodium hydroxide had been on trial for about a month before the chemical leak was detected. The amount of the chemical used in the trial phase was low so the impact of the leak is limited, according to the local authorities.

When the plant comes into full operation, it will use hundreds of times more sodium hydroxide, which is used at high temperatures to wash aluminum ore, so it would be much more difficult to control a leak in the future, said provincial officials.

Nhan Co alumina plant, with an estimated capacity of 600,000 tons of alumina a year, has been under construction since 2010. It is part of a bauxite and aluminum complex 300 kilometers northeast of Ho Chi Minh City.

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