An official at Sasol Secunda has accused the petrochemical giant of intentionally polluting the Vaal River.
The employee made submissions at the South African Human Rights Commission's (SAHRC) inquiry into the contamination of the river, held at Constitutional Hill in Johannesburg.
"Sasol excretes a type zero waste which is not allowed to be landfilled at all. And if it (Sasol) wishes to do so, it will have to treat it (the waste) to be type one, to reduce harm," he said.
Some residents in the Vaal claimed that the foul smell in the area made them sick and wanted their concerns to be attended to urgently.
The situation prompted the SAHRC to establish an inquiry to determine whether the spillage amounted to an infringement of basic human rights, and what may have caused the pollution in the first place.
The Emfuleni municipality, which is the most affected, has since been placed under administration and the mayor, Jacob Khawe, tendered his resignation in December.
Among some of the chemicals the whistleblower said Sasol continues to spill, is vanadium.
A quick Google search reveals that a person's exposure to vanadium may affect the central nervous system, with symptoms including headaches, abdominal cramps, diarrhoea and a green colour to the tongue.
Another chemical the Sasol official testified that his company unlawfully discharges is potassium carbonate, which can cause severe irritation of the gastro-intestinal tract and result in nausea, vomiting and burns.
"Those chemicals should never be allowed into a stream, and I have been advised that some of the chemicals can cause birth defects," the whistleblower said.
He also explained to the inquiry that he had been subjected to intimidation after he spoke out about the matter to his superiors.
"The intimidation is worsening despite the fact that I have followed proper procedures to report the irregularities to relevant authorities, I am just surprised that I am not shot in the head yet," he continued.
These revelations come despite Sasol having appeared before the same inquiry in November and denied its involvement in the pollution of the river from its Secunda plant.
The petrochemical giant at the time only conceded that it had struggled to interpret some compliance requirements about regulations on the discharge of waste.
Sasol also revealed that three of its incinerators were closed last year due to non-compliance.
The SAHRC's inquiry sat for the last time on Wednesday and its chairperson Buang Jones said "all written and verbal submissions will be considered, evaluated" and added so that a final report would be compiled in three months.
Earlier on Wednesday, the water and sanitation's Gauteng head Sibusiso Mthembu said that the South African National Defence Force's (SANDF) intervention at the severely polluted river has received a R240m cash injection.
R900m is still needed for the intervention, a mission which is set to be completed in March 2020, to be fruitful.
The SANDF deployed soldiers, among them specialist engineers, to find solutions to the contamination of the river.
As he closed the hearing, Jones said that his team would still be taking written submission until February 28.