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What Color is Diesel Fuel?

What Color is Diesel Fuel?

Diesel fuel is often associated with a distinct color that can range from a pale yellow or amber to a more vibrant dyed green or red coloration. The color of diesel fuel will vary depending on a multitude of factors, including regional regulations, additives, and its intended purpose!

Diesel fuel is typically a clear to yellowish liquid, but it can sometimes appear to be greenish-brown depending on the specific blend and additives. The exact color can vary, but it is generally lighter than motor oil, which is typically dark brown or black.

In this article, we will take a closer look at diesel fuel color and shed light on the factors that contribute to the different colors you may see.

Clear Diesel Fuel

Clear diesel fuel, also known as untaxed or on-road diesel fuel, refers to the standard, uncolored diesel fuel used in vehicles that operate on public roads. It is called “clear” because it does not contain any artificial dyes or colorants that are typically added to differentiate it from dyed diesel fuel.

Clear diesel fuel goes through a refining process to remove a wide range of different impurities and maximize its energy content.

It is commonly used in a wide range of vehicles, from everyday cars and trucks to buses, motorcycles, and even some heavy machinery!

You might also find clear diesel fuel used in backup power generators, large or small boat engines, and certain industrial equipment such as lathes and heating vats.

The different quality standards for clear diesel fuel are regulated by government agencies or fuel industry corporations to ensure the fuel provides the best performance in your vehicles while also reducing the environmental impact.

These standards include a variety of strict criteria such as minimum and maximum cetane number, sulfur content, lubricity, and volatility which all affect engine performance, emissions, and overall fuel efficiency.

Due to its widespread use in transportation and other normal industries, clear diesel fuel is widely available at gas stations around the country.

It is important to note that using clear diesel fuel in vehicles or equipment that require dyed diesel fuel for tax-exempt purposes can lead to legal consequences since it is considered a violation of taxation and fuel use regulations.

Closeup of diesel gas cap on car

Dyed Diesel Fuel

Dyed diesel fuel refers to normal diesel fuel that has been tinted or colored using dyes for specific purposes.

The process of dyeing diesel fuel involves adding a vibrant shade of red, blue, green, or another color of dye to very obviously tell it apart from regular untaxed diesel fuel.

The main reason dyed diesel fuel exists is to keep it separated from taxed and untaxed fuel.

In the United States and many other countries, dyed diesel fuel is almost exclusively used for off-road purposes or in industries like agriculture, construction, and forestry.

This dyed diesel fuel is sold at a lower tax rate due to its designated usage. By dyeing the fuel, government authorities can easily identify if it is being used appropriately or illegally in on-road vehicles which require the use of taxed and clear diesel fuel.

The specific regulations regarding the color and permitted usage of dyed diesel fuel vary between countries and regions and sometimes even from state to state.

For example, in the United States, the red dye of various vibrant hues is usually used for off-road diesel fuel, while the bright green dye is used for heating fuel.

In Canada, red dye is used for various non-taxed uses, while purple dye is used for heating.

Always keep in mind that while it may be cheaper in the long run, using dyed diesel fuel for unintended purposes or attempting to avoid paying taxes on that fuel can have serious legal consequences.

Authorities have a variety of different measures in place to detect the presence of dye in fuel, and penalties for illegal use or possession of dyed diesel fuel can include hefty fines and fees.

Diesel Fuel Taxing

Diesel fuel taxing is the process in which nationwide or industry-based governments require a set amount of taxes on the sale and use of specific diesel fuel mixtures.

These taxes are typically placed to generate revenue for various purposes, including the funding of transportation infrastructure, maintaining busy roadways, and supporting environmental initiatives.

The specific taxation policies and rates vary between countries and even within different regions or states of the United States and Canada.

The taxation of diesel fuel can take different forms. One common approach is to apply a per-gallon tax right at the pump or point of sale. This tax is typically included in the retail price of diesel fuel, which means you will pay the tax directly when purchasing that fuel to fill up your vehicle or portable container.

To add to the confusion, the tax rate can vary depending on factors such as the country’s overall economic policies, fuel consumption goals for the quarter or year, and environmental objectives.

In some cases, diesel fuel may even be subject to additional taxes or surcharges beyond the base tax rate. These additional charges can be used to support specific initiatives such as reducing vehicle or industrial emissions, promoting alternative fuel usage, or financing community transportation projects.

While the general public may not always approve, governments often use tax incentives and exemptions to encourage specific uses of different types of diesel fuel or to support certain industries. 

For example, dyed diesel fuel used for off-road purposes or in specific agricultural, construction, and forestry sectors may be subject to lower tax rates or even complete tax exemptions, depending on the jurisdiction and how the tax rules are written for that region.

This difference in regulations helps ensure that taxes are fitting for the intended use of the fuel and will potentially discourage illegal or improper usage of that fuel.

Tax enforcement on diesel fuel usage is an important aspect of taxing policies. However, it has been a common point of complaint among a large part of the general population!

Governments employ various measures to monitor your compliance with their regulations and to prevent tax evasion in addition to fuel dyeing, which can include periodic fuel quality testing and unannounced inspections of fueling stations and vehicles. 

If you found this article helpful, make sure to take a look at some of the other fuel color-related posts below!

Zach Reed

Hi, I'm the founder of! Having owned a wide variety of vehicles in my life, I was astounded at how hard it can be to find answers to common automotive questions. Rather than sit idly, I decided to create this website to help others!