"50 ppm" has become the password of every diesel tender in West Africa. Behind those few characters lie a regional standard, an unflattering history, and exceptions few buyers know about. Here is what it means, who really meets it, and how to make sure you receive what you paid for.
What 50 ppm means
"ppm" stands for parts per million. A 50 ppm diesel contains at most 50 milligrams of sulphur per kilogram of product, or 0.005 percent of its mass.
Sulphur does nothing for the engine. It pollutes. When burnt it produces sulphur dioxide and fine particles, and it poisons the after-treatment systems of modern engines. The lower the content, the cleaner the diesel.
For scale:
| Sulphur content | What it is |
|---|---|
| 10 ppm | European diesel (EN 590 standard, often called "Euro 5") |
| 50 ppm | ECOWAS ceiling for imports since 2021 |
| 1,500 ppm | Ceiling granted by waiver to Ghana's local refineries until the end of 2024 |
| more than 2,000 ppm | Diesel produced by SIR in Abidjan in 2026 |
Where the standard came from
In 2016 the Swiss NGO Public Eye published Dirty Diesel, an investigation showing that traders were selling fuels in West Africa with far more sulphur than Europe allowed, taking advantage of lax national standards. The scandal sped things up. In July 2017 Ghana cut the sulphur ceiling for imported diesel by a factor of sixty.
Then ECOWAS harmonised. Its directive C/DIR.1/9/2020 on automotive fuel specifications sets a ceiling of 50 ppm sulphur for petrol and diesel, with two deadlines:
- 1 January 2021 for fuels imported from outside ECOWAS;
- 1 January 2025 for fuels produced by refineries in the region.
Who really meets it in 2026
Imports, in principle yes. Cargoes arriving by sea in the region's ports must be at 50 ppm. Countries transpose the directive at their own pace: Togo adopted its new specifications on 11 July 2025.
Local refineries, not all of them. This is the blind spot of the standard. According to allAfrica, diesel from Société Ivoirienne de Raffinage still exceeds 2,000 ppm sulphur, and Côte d'Ivoire has until 1 January 2031 to bring it into line with ECOWAS rules. SIR is building a 545 billion CFA franc hydrodesulphurisation unit for that purpose, expected in 2030. In Ghana, the National Petroleum Authority likewise granted local refineries a 1,500 ppm waiver until 31 December 2024.
Dangote goes further. The Nigerian refinery says its diesel meets Euro 5, which means 10 ppm.
In practice, in 2026 "diesel sold in West Africa" does not mean "50 ppm diesel". It depends on where it comes from.
Why it matters to a buyer
Modern engines need it. Latest generation trucks, earthmoving equipment and generators are designed for low sulphur diesel. High sulphur fuel fouls their emission systems, and the repair costs far more than the saving at purchase.
Tenders require it. Mines, power plants and international organisations write the sulphur content into their specifications. Delivering off spec means risking rejection of the batch.
Health. Sulphur ends up in city air as sulphur dioxide and particles.
How to check a batch
Demand a certificate of analysis for every batch. It should state the sulphur content and the test method, along with the usual parameters: density, flash point, cetane, water content.
Compare it with the contract specification. For reference, the European EN 590 standard sets among other things a density of 820 to 845 kg/m³ at 15 °C, a cetane number of at least 51, a flash point above 55 °C and at most 10 mg of sulphur per kg.
Have large volumes tested. A sample taken on delivery and analysed by an independent laboratory settles any dispute. The supplier's certificate describes the batch when it left the depot; only a sample at arrival tells you what went into your tank.
And the price?
For consumers, 50 ppm diesel has no separate price: it is the pump price, since all imports must meet the standard. On 30 September 2026 it ranged from 618 CFA francs a litre in Niger to 940 in Bamako (see our country by country price table). SIR's management has also said its future desulphurised diesel will be sold at the same price.
For bulk purchases, the price is built from an international quotation for low sulphur gasoil, plus freight, storage, the country's taxes and transport to site.
Our reading
The 50 ppm standard is a real victory, won after a scandal. But it runs at two speeds: strict for imports, flexible for the region's refineries, which obtained extra time. For a buyer the rule is simple: never assume, always read the certificate. And for new fleets, aim lower than 50 ppm where possible.
Frequently asked questions
What does 50 ppm diesel mean?
Diesel containing at most 50 milligrams of sulphur per kilogram, or 0.005 percent of its mass. It is the ceiling set by ECOWAS.
Since when does the 50 ppm standard apply in West Africa?
Since 1 January 2021 for imported fuels, and in principle since 1 January 2025 for fuels from the region's refineries, with extra time granted to some of them.
Is 50 ppm diesel more expensive?
Not at the pump: all imports must already meet the standard and official prices apply. In bulk, the price follows the international quotation for low sulphur gasoil.
What is the difference between 50 ppm and 10 ppm diesel?
10 ppm diesel, the European EN 590 standard, contains five times less sulphur. It is what the Dangote refinery produces.
What we do
GraceRoad delivers diesel with a certificate of analysis for every batch and arranges independent testing on delivery for large volumes. Tell us the specification your site or tender requires and we will source accordingly.
Read next: adulterated diesel: how to spot it and West African refineries in 2026.
Sources: ECOWAS directive C/DIR.1/9/2020 on harmonised automotive fuel specifications, and Le Sahel, June 2023 (2021 and 2025 deadlines); Public Eye, Dirty Diesel, 2016, and campaign follow-up page (Ghana, July 2017); Ghana National Petroleum Authority (1,500 ppm waiver until 31 December 2024); allAfrica, 15 June 2026 (sulphur content of SIR diesel, 2031 deadline); Sika Finance, 11 June 2026 (SIR hydrodesulphurisation unit, unchanged price); Journal du Togo, July 2026 (Togolese specifications of 11 July 2025); Africanews, 23 March 2026 (Dangote Euro 5); European standard EN 590 (diesel specifications).