The department of forestry, fisheries and the environment (DFFE) says it is aware of reports of a strong sulphurous odour detected in several areas, particularly in Ekurhuleni and Johannesburg.
This comes after residents across parts of Gauteng have recently complained about a strong sulphur-like smell.
The department said the smell residents may be experiencing is because of elevated levels of hydrogen sulphide.
“The department can confirm that the stench experienced by residents in these areas is likely caused by hydrogen sulphide (H₂S). DFFE wishes to assure the public that the matter is receiving attention,” the department said.
The department said it received reports of the strong odour on Wednesday and began monitoring air quality data.
It said air quality monitoring information from the South African Air Quality Information System showed that levels of sulphur dioxide, while elevated, remained in compliance with National Ambient Air Quality Standards during this period.
“For hydrogen sulphide, monitoring data also showed elevated peaks, especially in Secunda, Springs, Irene (Pretoria), Midstream and Buccleuch air quality monitoring stations. Although there are no National Ambient Air Quality Standards for hydrogen sulphide for now, these pollution levels were all significantly higher than the World Health Organisation recommended threshold for ambient nuisance odour of 5.02 parts per billion,” the department said.
Based on these findings, the department said public complaints were most likely triggered by higher levels of the gas combined with certain weather patterns.
“Meteorological conditions show prevailing south-easterly winds that allowed for the transportation of air pollution from Mpumalanga into Gauteng, particularly over the cities of Ekurhuleni, Johannesburg and Pretoria,” the department said.
The department said during February 2022, similar sulphurous odour episodes were experienced across Mpumalanga and Gauteng.
Investigations at the time were conducted by DFFE together with air quality authorities from Mpumalanga, North West and Gauteng, with attention focused on operations at the Sasol Secunda Operations, a significant contributor to sulphur dioxide and hydrogen sulphide emissions.
The 2022 investigation found that a combination of industrial emissions, particularly from the Sasol coal-to-liquids plant, and unusual air circulation patterns caused the smell to spread into parts of Gauteng and the North West.
Although industries were operating within the legal emission limits at the time, ambient sulphur dioxide levels were higher than usual.
Following that incident, the department said a multi-stakeholder task team was established to investigate complaints and develop a long-term strategy to improve the management of sulphur dioxide and hydrogen sulphide emissions.
Several steps have since been taken, including increased monitoring.
The City of Johannesburg has invested in two additional hydrogen sulphide monitoring stations in Alexandra and Buccleuch. The government is also pursuing legislative changes aimed at reducing emissions.
“In August 2025, the minister of forestry, fisheries and the environment published, for public comment, a notice of intention to tighten the permitted release of hydrogen sulphide from coal gasification processes in terms of Section 21 of the National Environmental Management: Air Quality Act,” the department said.
The proposed amendment seeks to reduce the emission limit of hydrogen sulphide from 3,500mg per cubic metre to 600mg per cubic metre, which will significantly reduce pollution released into the environment.
The department said comprehensive comments were received from stakeholders, and the notice will be published for a second round of public consultations.
“It is anticipated that these regulatory provisions will be finalised and implemented during 2026,” it said.
A second legislative improvement under consideration is introducing hydrogen sulphide as a criteria pollutant under the National Environmental Management: Air Quality Act.
“This will allow South Africa to establish National Ambient Air Quality Standards for hydrogen sulphide, aligned with international health protection guidelines. Consultations with provinces and municipalities on these standards are currently underway.”
Health experts warn that exposure to hydrogen sulphide may cause irritation to the eyes and respiratory system.
Possible symptoms include dizziness, headaches, nausea, stomach upset, weakness, irritability and breathing difficulties.
“In severe cases, high exposure may lead to convulsions, loss of consciousness, or respiratory complications,” the department said.
The department also said children may be particularly vulnerable because they breathe more rapidly relative to their body size and may therefore receive higher exposure levels than adults in the same environment.
They also urged residents in affected areas to report persistent strong odours to local environmental health authorities, avoid prolonged exposure if the smell is present and seek medical attention if they experience ongoing respiratory irritation.
TimesLIVE
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