What is Red Diesel?

Michael Pollick
Michael Pollick

Not all diesel fuels have the same destination. Home heating oil, for example, is designated to be pumped into above-ground storage tanks and used as a source of heat. The diesel fuel in a home heating unit is atomized and then ignited to provide warmth. Diesel fuel for automobiles contains more sulfur than home heating oil, and is designed strictly for use in diesel engines. Automotive diesel fuel is also subject to taxes not levied on home heating oil. In order to tell the two fuels apart, a special red dye is added to home heating oil to create red diesel.

It is considered a criminal act to use red diesel for reasons other than home heating.
It is considered a criminal act to use red diesel for reasons other than home heating.

Red diesel fuel is only slightly different chemically from regular automotive diesel fuel, but there can be a significant difference in cost. The cheaper red diesel fuel could conceivably work in place of the more expensive automotive diesel fuel, but that would defeat the purpose of a fuel tax. In order to ensure that home heating oil, which is minimally taxed, is not used as diesel fuel, which can be heavily taxed, revenue agents require home heating oil to receive a special red dye. This liquid red dye can be detected in even the smallest samples taken for examination.

Red diesel differs from traditional automotive diesel fuel.
Red diesel differs from traditional automotive diesel fuel.

Using red diesel for reasons other than home heating is generally considered a criminal act, since the buyer did not pay the proper tax for regular diesel fuel. If there is reasonable cause to inspect a vehicle's fuel tank or storage tank, inspectors can quickly and conclusively identify the presence of red diesel and take appropriate action against the offender. Without the dye, it would take a trained chemist to differentiate between home heating oil and automotive diesel fuel.

Different countries use different solvent dyes to create their red diesel, but the purpose is generally the same. The dye has no negative effects on the fuel itself, but it does allow revenue agents to determine at a glance if a violation has occurred.

Michael Pollick
Michael Pollick

A regular wiseGEEK contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

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Discussion Comments


I had a guy calling me at work over and over, mad about repairs he needed to his engine. $8000 and still having issues. I talked to the dealership and they said 'we'd love to do $8000 of warranty work on his truck, but he's been using red diesel and it killed his truck. Since that's illegal we can't use warranty on that. This is abuse of the engine.'

Well, pay the extra dollar for real fuel! If all the guy ran was red diesel he probably saved like $4500 by the time he needed an $8000 customer-pay repair. Rocket science. He literally used red diesel the next fuel up after they overhauled his whole fueling system and had the emissions warning come up that he had 175 miles before it went into limp again. A dollar.


Red diesel is no different than "normal diesel" really. The only difference between the two are one has had a dye added to it so HMRC can spot it easily.


I would like to use red dyed diesel fuel in an airplane, fitted with a Subaru diesel engine.

Is that legal or do I have to use Jet AA fuel, for which the engine might not be suitable?


Which company is supplying those tablets to the customs?


What is the composition of the tablets that customs use to convert red dyed diesel into clear diesel?


"forecourt operative filled my fuel tank with red diesel by mistake."

I've never ever seen red diesel sold on a fuel station forecourt!


Red diesel is exactly the same as regular diesel so therefore gives the same starting, running and emissions. It has the same additives and anti waxing properties and would produce the same power as road diesel. But the risks far outweigh the gains if caught! They don't just need to dip your tank as they have a type of exhaust tester that senses the burnt dye.


if the truck is registered you cannot legally run red diesel and if they check your tank, you will be charged by the gallon. that's also the downside of running transmission fluid in the tank. if they test, it's red and a lot of times gets mistaken for red diesel.


Anyone know where I can get these tablets from?


What is the Higher Heating Value (HHV) of red diesel?


red diesel can be used in one tank for off-road use and non-dyed fuel in another with a method of stopping dyed fuel for road travel on the same vehicle.


Just how assiduous is HMR&C in policing what to many of us is an unjustifiable subsidy of people who are relatively well off?

How much tax is 'avoided' by red diesel?


To keep it simple if you have a question about whether or not you can use red diesel, you most likely can't.

To my knowledge only vehicles used strictly for farming, heating (and the like), and by some government organizations are allowed to legally use red diesel.

So private vehicles you'll think about driving on a road ever? No, sorry, no red diesel. A tractor used for agriculture only, yes.


I have an old pick up which i use to feed my cattle. can I use red diesel as fuel?


Red diesel is the exact same as regular diesel. It just has dye to identify what it is. No, only vehicles that are not solely purposed for the road can use it, because they do not have to pay road tax.


Red diesel is also used for emergency generators- not just for home heating purposes. - Fire and Safety Engineer.


can red diesel be used to run a trailer for a food transport company


does the green diesel dye degrade or yellow if an underground storage tank leaks into soil? we are recovering what started out as green diesel and from the same wells is changing to yellow. How do we find constituents of the dye for remediation reasons?


Is red diesel legal for school bus use?


How is Red Diesel produced?


see how its illegal to have red diesel in the tank of your motor for every day driving about but if i had the dye put in my tank would that make it legal.


I'm not sure what chemicals are in that tablet, but my guess would be that officials don't exactly advertise where they obtain them. If an unscrupulous commercial driver intentionally filled his rig with cheaper but illegal red diesel, all he would have to do is drop a version of that tablet into the tank before inspection and it would test as legal white diesel.

Each jurisdiction is permitted to use its own red dye, so there would be no guarantee that a tablet formulated for one type of dye would work for a different type of dye. If such a honest mistake had been made elsewhere, you may have had to have your entire tank drained and replaced with white diesel. Those tablets certainly saved everyone a lot of time, but I'm sure the customs official would have to be convinced it was a mistake before dropping one in a tank.


As a truck driver and owner i was in a position where a forecourt operative filled my fuel tank with red diesel by mistake. Due to this action i notified the customs & excise who without hesitation arrived and produced a tablet which was inserted into my tank.

After twenty minutes all the red diesel was cleaned and reverted to white. What i would like to know does anybody know what the substance was used in cleaning the diesel. By the way the garage was charged £1300.


Can I use red diesel fuel in my Ford 2006 6.0L here in the United States?


Does red diesel fuel create more pollution than regular diesel fuel?

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