US EPA — Notice of Violation to Volkswagen (2015)
PDF · 6 pages · 2 MB
What this document is
This is the ‘Notice of Violation’ that the United States Environmental Protection Agency sent to Volkswagen on 18 September 2015. In it, the EPA formally alleged that the carmaker had breached the US Clean Air Act by fitting certain diesel vehicles with software designed to cheat emissions tests.
The notice is the document that first made the scandal public and set the affair widely known as ‘dieselgate’ in motion. This page summarises what the notice was and why it mattered, from established general knowledge; for the exact allegations and legal wording, please consult the EPA’s original.
What it covers
At its heart, the notice concerns a mismatch between how the affected vehicles behaved during official testing and how they behaved on the road. Its broad substance includes the following.
- The allegation that a ‘defeat device’ in the engine software recognised test conditions;
- The claim that emissions controls were reduced during normal driving, raising nitrogen oxide output;
- The identification of affected diesel models and engine types;
- The statement that this constituted a violation of the Clean Air Act;
- The regulatory basis for requiring the manufacturer to respond and remedy the issue.
What began as a technical regulatory notice quickly escalated into one of the largest corporate scandals in the motor industry, with recalls, penalties and legal action following in many countries.
Why it matters
The notice exposed how far real-world vehicle emissions could diverge from laboratory tests, prompting a global rethink of how cars are tested and regulated. It sharpened public scrutiny of diesel and helped accelerate interest in cleaner alternatives, including electric vehicles.
Because it was so widely reported and linked, many external references to the original PDF now fail. A stable summary preserves the reference for readers arriving from those sources.
How it relates to the UK
The scandal reinforced concerns about urban air quality and hastened the shift towards electric cars — a shift with direct energy implications, from home charging to the electricity tariffs that suit EV owners. Our environment guides cover electric vehicles, charging and low-carbon living in a UK context.
You can read the EPA’s materials on the case via the EPA Volkswagen information pages.
Frequently asked questions
What is a Notice of Violation?
A Notice of Violation is a formal notice from a regulator stating that it believes a party has broken the law — in this case, that Volkswagen had violated the US Clean Air Act. It is a regulatory step, not itself a court judgment.
What did the EPA allege?
The EPA alleged that certain Volkswagen diesel vehicles contained software — a so-called defeat device — that detected when a car was being emissions-tested and reduced pollutant output during the test, while emitting more on the road. This is the essence of what became known as dieselgate.
Which pollutant was at the centre of the case?
The core concern was nitrogen oxides (NOx), pollutants linked to poor air quality and respiratory harm, which the vehicles were said to emit at far higher levels in normal driving than during testing.
Where can I read the original notice?
The EPA published the notice and maintains information pages on the case. This page links to the EPA’s Volkswagen resources.