The environment, Forestry and Fisheries department (DEFF) said on Wednesday that it would investigate the “elevated levels” of sulphur dioxide and hydrogen sulphur experienced in parts of Gauteng and Mpumalanga since the weekend.

The department, together with Gert Sibande district municipality in Mpumalanga, will on Thursday check up on the Sasol operation in Secunda, which is believed to be a possible source of the smell.

“The stench is likely a combination of elevated levels of sulphur dioxide and hydrogen sulphide,” said the department. It said that as part of the investigations, authorities were asking the Sasol facility to account in terms of section 30 of the National Environmental Air Quality Management Act (NEMA) and to put mitigation measures in place should they be found to be the source of the smell.

“Section 30 relates to the control of environmental incidents, such as leaks, or the uncontrolled release of a hazardous substance that may cause harm to people and the environment,” the department said.

The department said the authorities will decide on any further course of action once the investigations were complete.

“While there are many sources in the area that could be contributing to these elevated levels, the district municipality’s air quality officer has been informed that the Sasol Secunda operation is experiencing stressed conditions as the facility started ramping up operations.

“From the ambient air quality monitoring observations on the South African Air Quality Information System (SAAQIS), sulphur dioxide ambient levels, while elevated, have remained in compliance with ambient standards in Johannesburg, Pretoria and Mpumalanga,” said the department.

The department said the pollutant causes an odour nuisance even at concentrations far below those that cause health hazards.

“People who are sensitive to unpleasant odours are likely to experience headaches and nausea,” said the department.

TimesLIVE