What Color Is Diesel Fuel? Significance of Different Colors

Many don’t have an idea what color is diesel fuel, and that’s totally understandable. A lot of car owners don’t pay any real attention to the color of the fuel at gas stations.

What Color Is Diesel Fuel

With this in mind, you may be shocked to know that there are different colors for diesel fuel, and even more significantly, the different colors have legal implications.

If this intrigues you, then you have come to the right place, as we will consider this topic in detail.

What Colors Can Diesel Fuel Have?

Diesel fuel can have colors like red, blue, green, and yellow, and it can also be clear (without color). This may surprise many, considering how little attention is paid to the fuel color in gas stations. However, these colors are not for aesthetic appeal and have real-life legal significance

While diesel is normally clear with a slightly yellow hue, there are times when it can be dyed to give it the different colors that are highlighted. For instance, for red diesel, the red dye is not to make the diesel flashier or appear more vibrant but serves as a marker for legal reasons. 

When diesel is dyed, its density slightly reduces. However, the performance of diesel fuel is not in any way affected, although there may be more pollutants with dyed diesel

What Do the Different Diesel Fuel Colors Mean?

The different diesel fuel colors mean there are differences in the taxing of the fuels and the vehicles that are permitted to use the different fuels. In fact, dyed diesel is often referred to as tax-exempt diesel because of the lower taxes typically imposed on them.

It is critical for car owners to know what these different colors mean in diesel fuel, and we have you covered below. 

– Clear Diesel

This is the most typical diesel fuel today, as it is the only one approved for on-road vehicles among civilians. For this reason, it is referred to as onroad diesel fuel. This type of diesel is very low in sulfur and can also be known as ultra-low sulfur diesel. This fuel is denser than its dyed counterparts.

Clear Diesel

While the diesel is known as clear or regular diesel, it may have a slightly yellowish or amber hue. But you can still quite clearly tell it apart from yellow diesel. If you have a diesel-powered vehicle, this is the only type of fuel you can use. Aside from public vehicles, marine vehicles also use this type of diesel.

– Red Diesel

The most conventional dyed diesel in the United States is red diesel, also known as tax-exempt diesel fuel. This diesel type is dyed red with Solvent Red 26 or 164, which are chemical dyes. While the color is different, the performance of this diesel is the same as the clear ones.

In other words, you will not be able to notice any performance differences if you use red diesel in your car. However, red diesel has a higher sulfur content than its clear counterparts. Therefore, it will produce more polluting fumes when it is used.

While you will not expect any difference in performance when using this fuel, it is only approved for off-road use. Therefore, only vehicles used off public roads, particularly vehicles in the agricultural and construction industries, can use this fuel. This includes cranes, forklifts, tractors, excavators, etc. 

This type of fuel is not taxed by the United States government, which justifies its tag, “tax-exempt fuel.” The reason for not taxing it lies in the government trying to encourage and promote agricultural, construction, and similarly useful off-road industrial purposes. 

– Blue Diesel

This diesel is entirely identical to regular diesel in chemical composition, performance, and pollutant fumes, with the only difference being its blue color.

Blue Diesel

However, blue diesel fuel can only be used in government vehicles and as such, is heavily regulated by the governmentAs you would imagine, you will be incurring the wrath of the law if you use this fuel in your vehicle for any reason. 

– Green Diesel

This is similar to red diesel, with the only difference being its green rather than red color. This fuel is not at all common in the United States but may be the predominant diesel fuel in some regions. 

As with red diesel, green diesel fuel is only approved for off-road use, and using it on public roads can attract litigation cases and fines

– Yellow Diesel

Again, this is identical to red diesel, with the only difference being its yellow color. This seems to be the rarest of the diesel fuel types, and chances are that you will never see it in the United States. It can only be used in off-road vehicles and never on public roads.

Is It Legal To Use Red Diesel in Your Car?

No, it is not legal to use red diesel in your car. If you use it, you can be charged with hefty fines and may even be sued as a tax evader, depending on the laws of your region. There are only specific businesses that are allowed to use this.

Is It Legal To Use Red Diesel in Your Car

This is important to note as many are tempted to use the fuel because of its tax exemption. The reason this fuel is illegal for use is that the government specially approved this dyed diesel fuel to relieve agricultural and similar industrial businesses. Since this fuel is tax-exempt, it provides some form of financial relief for these businesses.

Another reason many have postulated is that red diesel emits more pollutants and is, therefore, illegal for on-road use. However, this argument is not very solid. While this fuel contains more sulfur, it is still very similar to regular diesel fuels, and it is very unlikely that the impact on the environment is significant. 

Take note that while red diesel is solely an off-road diesel, you can still use clear fuel for off-road vehicles. It will not be in your best interests, though, considering the tax rebates on red fuel, but there is no legal risk to using clear fuel for off-road vehicles.

What Happens When You Use the Wrong Color of Diesel?

When you use the wrong color of diesel, you may incur massive fines and even be charged in court, depending on the circumstances. However, there is no loss in performance, and it is impossible to tell the fuels apart when driving.

This is because all the fuels are chemically similar, and only slight differences exist between them. For some fuels, like blue fuel and clear fuel, the only difference is in the color of the fuel. While dyed fuels are typically not as dense, that has no impact on the performance of the vehicle. The only difference may be the increased amount of pollutant fumes, albeit marginal.

However, the increase in pollutant fumes is the least of your worries if you use the wrong color of diesel. You can be fined and even arrested, depending on the situation. The fine could be as much as 1,000 dollars or 10 dollars per gallon of fuel purchase – whichever is more. 

Luckily for you, regular diesel fuel is distinctly sold in gas stations, so there’s little risk of negligence or mistakenly filing your car with the wrong color of fuel. Still, there is no harm in checking to confirm if you are in unfamiliar stations or are simply unsure. 

Is Red Diesel Cheaper Than Clear Diesel?

Yes, red diesel is cheaper than clear diesel, as this type of diesel is approved to relieve the financial obligations of agricultural and other related businesses. The government effects this lower cost by exempting these fuels from taxes. In other words, you don’t pay tax on red fuel.

Is Red Diesel Cheaper Than Clear Diesel

If you don’t pay tax on red fuel, does that mean you pay tax on clear fuel? Yes, that’s what it means. At the point of purchase, tax is levied on the fuel, and you simply cannot avoid this tax as it is added to the price of the fuel you buy

There is no general price for red color diesel fuel. Instead, different states have different prices for red diesel fuel. On average, you can save around 25 cents per gallon on red diesel fuel compared to regular diesel. However, in some states like Washington, you can save as much as 74 cents per gallon


Many are unaware, but there are different colors of diesel fuel, and they have different implications when used in your car.

These are key takeaways from the article:

  • Diesel fuel can be dyed or clear, with the former representing off-road use, while the latter is for on-road use.
  • What color is diesel fuel has these answers: clear, red, blue, green, and yellow.
  • Dyed fuel is typically cheaper than clear fuel as the government offers tax rebates for the dyed fuel to favor agricultural, construction, and similar businesses.
  • It is illegal to use dyed duel for off-road vehicles, and doing so may incur hefty fines, and you may even be charged in court as a tax evader.
  • While the red diesel illegal status is set, there is no difference in performance, although there may be slightly more pollutant fumes emitted.

Now that you understand the legal implications, do well to avoid using the wrong color of fuel in your car. However, there is no need to panic about the safety of your engine or car if you use the wrong diesel fuel color by accident, as all fuels have similar compositions. 

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