Many people in the central Vietnam's Quang Ngai Province felt short of breath this past week due to toxic gases emitted by Dung Quat, the country's first oil refinery.
Managers from Dung Quat Economic Zone, where the refinery is located, tested three samples of the gas on Monday.
All of them contained unacceptable levels of sulfur dioxide (SO2). One sample registered more than twice the permitted amount.
Le Tran Quang Huy, Head of the Environment and Natural Resources Department at Dung Quat Economic Zone said "the harmful emission will largely affect people's health."
Local authorities have concluded that the gas came from the refinery; the refinery's investor, PetroVietnam (a subsidiary of Binh Son Petrochemical Refinery Co.) has admitted as much.
Ngo Van Thinh, a local commune official, said they asked Binh Son Company to stop emitting the gas.
Nguyen Hoai Giang, General Director of Binh Son, said the sulfur treatment plant at the refinery stopped operations last Wednesday to adjust it's catalyst.
Following the changes, the sulfur should be burned off by a torch system every day.
Giang said he couldn't stop the whole refinery as the economic losses would be too great.
He said his engineers are working hard to put the treatment plant back into operation soon. The plant treats sulfur to sell to chemical firms for the production of sulfuric acid.
Inhaling sulfur dioxide is associated with acute respiratory symptoms and disease, difficulty in breathing, and premature death, according to the US Environmental Protection Agency.
"The gas smelled like oxy-fuel welding (which produces acetylene)," said Nguyen Thanh Nhon, a local resident. "It was so strong that my family experienced difficult breathing for many days. We had to close our nose at meals."
Nhon lives very close to the refinery, so he's afraid that his children could develop respiratory ailments.