Contaminated diesel problem in South Africa

The Fuels Industry Association of South Africa (Fiasa) has welcomed the recent crackdown by tax authorities and law enforcement authorities on the illicit trade and production of adulterated diesel.

The association applauded the South African Revenue Service (SARS) and the police’s National Joint Operational and Intelligence Structure for their recent operations in this area.

It explained that the actions have disrupted large-scale criminal activity and led to the seizure of nearly two million litres of adulterated diesel.

SARS released a statement over the weekend about one such crackdown, where 23 targets were raided across Gauteng, Mpumalanga, and KwaZulu-Natal, resulting in the seizure of:

• 953,515 litres of contaminated diesel and other assets to the value of R367.27 million
• Two so-called fuel “washrooms,” including a rare mobile “washroom” fitted on a transport truck, used to remove paraffin markers
• 12 fuel transport trucks with false declarations of an average 15,000 litres of imported fuel per tanker

The authorities also found that six fuel depots were in contravention of Section 37 of the Customs and Excise Act and registered 13 criminal cases for prosecution.

Sars said that countries along the Maputo Corridor — including South Africa, Swaziland, and Mozambique — had become primary targets of the illicit fuel trade in the past decade.

“Sars has established that some importers declare fuel amounting to 40,000 litres or less, whereas investigation reveals that up to 60,000 litres of fuel are imported,” it explained.

SARS has also observed a national trend in which many fuel storage and distribution depots were involved in the adulteration of all fuel products, primarily through the illegal mixing of diesel with paraffin.

Fiasa’s Chief Executive, Avhapfani Tshifularo, said the actions reinforced the urgent need to eliminate criminal syndicates that exploit regulatory loopholes, smuggle fuel, and produce adulterated diesel.

“The illicit activities not only deprive the fiscus of an estimated R3.6 billion annually but also undermine fair competition, damage engines, pollute the environment, and erode public trust in the fuel industry.”

Tax adjustments needed

Tshifularo cautioned that the enforcement blitz needed to be sustained and required further long-term interventions.

“The nature of the illicit fuel economy is sophisticated and entrenched,” he said. “Criminal networks are agile, well-financed, and operate with transnational reach, especially along high-risk corridors.”

“To effectively combat this threat, South Africa must adopt a sustained, systems-based enforcement model.”

Tshifularo said the association has consistently and proactively advocated for a zero-tolerance approach to illicit fuel trade and proposed a comprehensive strategy to eradicate fuel adulteration.

Tshifularo explained that the significantly lower taxes on paraffin compared to diesel created a financial incentive for unscrupulous operators to blend the two fuels and sell the mixture as compliant diesel.

“This practice is not only illegal, but also economically destabilising and environmentally hazardous,” Tshifularo said.

“By taxing paraffin at the same rate as diesel, we would remove the profit motive that perpetuates adulteration, and level the playing field for law-abiding fuel producers, importers, and distributors.”

Tshifularo argued this single policy change would “strike at the heart” of the adulteration economy and support broader enforcement efforts.

Big engine problems

The issue of adulterated diesel in South Africa’s fuel supply chain is nothing new. The problem first emerged during the early 2000s and required in-depth research to solve.

Adding paraffin to diesel weakens its lubricity properties, which is a core requirement for a diesel engine. Another problem is that diesel is contaminated with hard dust particles along the fuel supply chain.

This diesel can cause substantial damage to engines, particularly those equipped with a high-pressure common rail injection system.

A team of mechanical engineers at the University of Pretoria, led by At von Wielligh, performed a study that showed how contaminated diesel caused combustion disturbances through fuel injector failure.

“The injector failed due to the fact that the needle became sticky in its movement and did not close properly,” the study explained.

“The result of this stickiness of the needle is that the droplet sizes increased dramatically. In some cases, the fuel was emitted in a jet of fuel, emitted from the injector tip orifices.”

Due to poor spraying patterns, the engine pistons can become damaged, seized, or even melt away. In another case, the lubricating oil was diluted, and the bearings on the crankshaft were damaged.