Heating oil and diesel are both No. 2 distillate from the middle of the barrel, and a gallon of one has about the same energy as a gallon of the other. What separates them is paperwork the fuel carries: highway diesel is made to the ASTM D975 engine specification, at 15 ppm sulfur or less and taxed, while heating oil is made to the ASTM D396 burner specification and is dyed red and untaxed for road use.
The practical questions people search sit in the gaps between those rules: whether one can be used in the other’s equipment, why the two prices differ and what the red dye is for. The answers below come from the specification values, the tax rule and a dated price comparison from EIA series; the forces behind each price are in Diesel Prices, Explained and Heating Oil Prices, Explained.
Two specifications for one kind of liquid
ASTM International writes the specifications. D975 covers diesel fuel oils for compression-ignition engines; D396 covers fuel oils for burners. The standards themselves are sold, so the values below come from public summaries of each and are labeled. Where the summaries do not show a property for a grade, the table says so instead of filling the cell.
Table 1. What each rulebook says about a No. 2 grade
| Property | Diesel, ASTM D975 No. 2-D S15 | Heating oil, ASTM D396 No. 2 | Where it matters |
|---|---|---|---|
| Intended use | Compression-ignition engines on and off the road | Domestic and small industrial burners (furnaces, boilers) | Different tests for different equipment |
| Flash point, minimum | 52 C (125 F); 38 C (100 F) if a cloud point below minus 12 C is specified | 38 C (100 F) in the Maryland regulation that adopts D396 | Handling and storage safety |
| Sulfur ceiling of the S15 grade | 15 ppm | No federal limit on heating oil; 15 ppm where states require it (New York, Delaware, New Jersey, New England and Maryland are the ones sourced here) | Emissions and aftertreatment damage |
| Cetane number, minimum | 40 | Not a property of the D396 grade; the Maryland text applies the diesel cetane rule to off-highway No. 2 unless it is sold as burner fuel only | Ignition quality in an engine; irrelevant to a flame |
| Lubricity (HFRR wear scar), maximum | 520 microns | Not listed in the summary reviewed | Injection pump protection |
| 90 percent distillation point, maximum | 338 C (640 F); minimum 282 C | 338 C (640 F) for No. 2 in the Maryland text | Same boiling range at the heavy end |
| Pour point, maximum | Low-temperature operability required by cloud point, CFPP or LTFT; no numeric limit in Table 1 | Minus 7 C (20 F) for No. 2 in the Maryland text | Outdoor tanks in winter |
| Water and sediment, maximum | 0.05 percent | 0.05 percent by volume in the Maryland text | Filter clogging |
| Dye | Undyed for highway use; dyed red if untaxed | Dyed red | Tax status, see below |
| Heat content (EIA) | 137,381 Btu per gallon | 138,500 Btu per gallon | About 0.8 percent more heat in heating oil |
Sources: ASTM D975 values from ALS Global's Table 1 overview and DieselNet's US diesel standards page; D396 No. 2 values from Maryland COMAR 03.03.05.04, which adopts ASTM D-396 with stated limits; Btu from EIA's British thermal units page. All checked October 23, 2026. ASTM's own pages were not retrievable.
Read the cetane and lubricity rows together. A diesel engine ignites fuel by compressing it, so cetane number (how readily the fuel ignites) and lubricity (the fuel lubricates the injection pump) are written into the engine fuel specification. A furnace sprays fuel into a flame that is already burning, so the burner specification does not need to guarantee ignition quality, and the D396 values reviewed here carry no lubricity limit. That is the technical reason the two are not interchangeable in the direction that matters most, heating oil in an engine, even though they share a boiling range at the heavy end and a flash point floor that differs by only 14 degrees Celsius.
What this table does not say
A tank of fuel sold as one grade may also meet the other grade’s numbers. The point of a specification is what the seller promises. When dyed ultra-low-sulfur fuel is delivered as heating oil, the promise made on the ticket is the burner one, and it carries no promise about cetane or lubricity.
Where the two names come from in the refinery
The EIA says U.S. refineries make an average of 11 to 12 gallons of diesel fuel from each 42-gallon barrel of crude oil, and describes diesel and heating oil as closely related products called distillates. Statistically they are even closer: EIA inventory, production and demand tables report distillate fuel oil as one pool, not as separate heating and driving fuels. In the weekly figures dated October 16, 2026, that pool held 104.3 million barrels in stock, with production of 5.232 million barrels a day and demand of 3.732. A Northeast homeowner’s delivery and a trucking company’s fill draw on the same inventory, which is why the two prices move together. The PADD districts guide explains the regional split of that pool.
The paperwork diverges after the refinery. Fuel leaves a terminal either undyed, for taxed highway use, or dyed red, for uses on which the road taxes are not owed. Heating oil is the dyed route with a heating spec on the ticket, and the same logic applies to off-road diesel for farm and construction equipment. The chemistry between a gallon of dyed ultra-low-sulfur diesel and a gallon of ultra-low-sulfur heating oil can be nearly the same. The labels, the ticket and the legal uses are not.
The red dye is a tax marker, and the numbers behind it
Federal excise tax on diesel fuel and kerosene is $0.244 a gallon, according to IRS Publication 510 (revised December 2025). Fuel that meets the dyeing requirements and is sold for an exempt use pays only the $0.001 per gallon leaking-underground-storage-tank (LUST) fee. The same publication defines diesel fuel as any liquid suitable for use in a diesel-powered highway vehicle or train, and the exclusions it lists are No. 5 and No. 6 fuel oils covered by ASTM D396 and military fuel F-76. By that definition No. 2 heating oil is diesel fuel for tax purposes. It is why the dye matters: it is the evidence that the fuel was removed for an untaxed use.
Table 2. The federal tax and dye arithmetic per gallon
| Item | Value | How it is derived |
|---|---|---|
| Federal tax, undyed diesel or kerosene | $0.244 per gallon | IRS Publication 510, taxable events |
| Federal fee on dyed fuel (LUST) | $0.001 per gallon | IRS Publication 510, dyed diesel fuel and dyed kerosene |
| Federal tax gap per gallon | $0.243 | $0.244 minus $0.001 |
| Dye standard | 3.9 lb of Solvent Red 26 equivalent per 1,000 barrels | 26 CFR 48.4082-1(b), Solvent Red 164 |
| Gallons in 1,000 barrels | 42,000 | 1,000 x 42 U.S. gallons |
| Dye solid per gallon | 42.1 mg | 3.9 lb x 453.59 g per lb / 42,000 gal |
Sources: IRS Publication 510 (Rev. 12-2025) and 26 CFR 48.4082-1, checked October 23, 2026. The last row is this page's arithmetic. State and local fuel taxes are additional and vary.
Who enforces the dye is a point many pages get wrong. Before June 2010, EPA rules also required dye and a marker in some diesel and heating oil. EPA now says there are no EPA requirements to dye any diesel fuel at the refinery gate and no presumption that undyed fuel is highway fuel, and that the dye requirement comes from the IRS, which requires untaxed diesel, including heating oil, to be dyed before it leaves the terminal. The EIA’s heating oil page summarizes the effect for households: red-dyed fuels are exempt from the road taxes and illegal to use in vehicles that normally operate on roadways.
What the penalty arithmetic looks like
Internal Revenue Code section 6715 sets the penalty for selling dyed fuel for a taxable use, using dyed fuel in a vehicle on the road with knowledge or reason to know, or altering the dye. The penalty on each act is the greater of $1,000 or $10 for each gallon of dyed fuel involved, in addition to any tax, and the $1,000 portion increases for repeat violations. The break-even is 100 gallons: below that the $1,000 floor governs, above it the per-gallon amount does.
Table 3. The statutory penalty against the federal tax gap, for stated quantities
| Gallons of dyed fuel involved | Penalty, first violation | Federal tax gap on those gallons | Penalty as a multiple of the tax gap |
|---|---|---|---|
| 20 | $1,000 | $4.86 | 206x |
| 50 | $1,000 | $12.15 | 82x |
| 100 | $1,000 | $24.30 | 41x |
| 150 | $1,500 | $36.45 | 41x |
| 500 | $5,000 | $121.50 | 41x |
| 1,000 | $10,000 | $243.00 | 41x |
Penalty: 26 U.S.C. 6715(b), greater of $1,000 or $10 per gallon (Cornell LII text, checked October 23, 2026). Tax gap: $0.243 per gallon federal only. These are statutory formulas, not predictions of what any enforcement action would produce.
The ratio column is the lesson of the rule. At 20 gallons the $1,000 floor is 206 times the federal tax avoided. From 100 gallons upward the $10 per gallon term governs and the multiple settles at 41 times, because penalty and tax both scale with gallons. The design makes the dye cheap to follow and costly to ignore.
Sulfur: the rule that arrived state by state
Highway diesel moved to 15 ppm sulfur years before heating oil did, because the engine rules came from EPA and the heating oil rules came from states. The EPA diesel standards page says the agency began lowering sulfur in diesel in 2006 and that all highway diesel was ULSD after 2010; nonroad, locomotive and marine diesel followed from 2007 to 2014. DieselNet’s summary of the federal rule adds that heating oil, and fuel for stationary engines, are exempt from the 15 ppm requirement.
Table 4. When each fuel class reached 15 ppm
| When | What changed | Source |
|---|---|---|
| 2006 to 2010 | Highway diesel to 15 ppm (ULSD) | EPA diesel standards page: phased in from 2006, all highway diesel ULSD after 2010 |
| 2007 to 2014 | Nonroad, locomotive and marine diesel to 15 ppm | EPA: 500 ppm step, then ULSD, all NRLM diesel ULSD after 2014 |
| 2012 | New York requires heating oil at 15 ppm or less | EIA, Heating oil explained: the first state to do so |
| 2016 | Delaware and New Jersey follow | EIA, Heating oil explained |
| July 1, 2018 | All six New England states follow | EIA, Heating oil explained |
| July 1, 2019 | Maryland: No. 1 and No. 2 fuel oil to 0.0015 percent sulfur by mass (15 ppm) | Maryland COMAR 03.03.05.04, adopting ASTM D396 with limits |
Sources: EPA diesel fuel standards page, EIA Heating oil explained, DieselNet US diesel standards and Maryland COMAR 03.03.05.04, all checked October 23, 2026. Other states may have their own rules or none.
The result is a patchwork. In the Northeast, where the EIA notes most U.S. residential heating oil is consumed, delivered heating oil is now commonly ultra-low sulfur, and the product a dealer loads for a furnace can be physically the same as the fuel at a diesel pump apart from the dye. Elsewhere the label matters more. The sulfur ceiling a fuel meets is printed on the delivery ticket as the S15 or S500 grade or as a ppm figure, and it is the one line that answers whether a heating-grade fuel could ever be suitable for an engine fitted with modern emissions equipment.
Heat content and what a million Btu costs
The EIA lists diesel fuel at 137,381 Btu per gallon and heating oil at 138,500. A gallon of heating oil therefore carries 0.81 percent more energy than a gallon of diesel, a gap too small to explain any real price difference between the two fuels. The price differences in the table below come from taxes, margins and delivery costs. The table converts the October 2026 prices to dollars per million Btu so the two fuels sit on one scale. The fuel comparison guide extends the same conversion to propane, gas and electricity.
Table 5. Prices in October 2026 per gallon and per million Btu
| Price point | Date | Per gallon | Per million Btu |
|---|---|---|---|
| NY Harbor No. 2 heating oil spot | Week ending 10/16/26 | $4.762 | $34.38 |
| NY Harbor ULSD spot | Week ending 10/16/26 | $5.027 | $36.59 |
| U.S. wholesale heating oil, no tax | Week of 10/19/26 | $5.323 | $38.43 |
| U.S. residential heating oil, no tax | Week of 10/19/26 | $6.190 | $44.69 |
| U.S. retail on-highway diesel, taxes included | Week of 10/19/26 | $6.276 | $45.68 |
Sources: EIA weekly spot prices (series EER_EPD2F_PF4_Y35NY_DPG and EER_EPD2DXL0_PF4_Y35NY_DPG), EIA Heating Oil and Propane Update (W_EPD2F_PWR_NUS_DPG and W_EPD2F_PRS_NUS_DPG) and EIA weekly retail diesel (EMD_EPD2D_PTE_NUS_DPG), all checked October 23, 2026. Btu factors from EIA. Spot weekly values are averages of daily closes, so the dates differ from the survey weeks by up to three days.
The residential heating oil price, with no taxes in it, is within 8.6 cents of the retail diesel price with taxes in it. Subtract the federal $0.244 from the diesel price and the order flips: the diesel pump price without federal tax is $6.032, 15.8 cents below the residential oil price. Dyed fuel is untaxed, but the household does not get a tax-free bargain, and one likely reason is that delivering a few hundred gallons to a house costs more per gallon than selling at a pump.
The wholesale gap, 2007 to 2025
At the wholesale level the two grades trade as separate New York Harbor spot assessments. The EIA publishes a No. 2 heating oil series and an ultra-low-sulfur diesel series. Subtracting one from the other, year by year, isolates the grade premium. The table also adds the U.S. retail diesel price and the gap between it and the New York Harbor ULSD spot, which is everything that happens between the spot market and the pump: freight, terminal fees, retail margin and taxes.
Table 6. Annual averages, NY Harbor spot grades and U.S. retail diesel, dollars per gallon
| Year | No. 2 heating oil spot | ULSD spot | ULSD minus heating oil (cents) | Premium as % of heating oil | Retail on-highway diesel | Retail minus ULSD spot |
|---|---|---|---|---|---|---|
| 2007 | $2.031 | $2.152 | 12.1 | 6.0% | $2.885 | $0.733 |
| 2008 | $2.855 | $2.976 | 12.1 | 4.2% | $3.803 | $0.827 |
| 2009 | $1.646 | $1.699 | 5.3 | 3.2% | $2.467 | $0.768 |
| 2010 | $2.127 | $2.198 | 7.1 | 3.3% | $2.992 | $0.794 |
| 2011 | $2.948 | $3.017 | 6.9 | 2.3% | $3.840 | $0.823 |
| 2012 | $3.023 | $3.113 | 9.0 | 3.0% | $3.968 | $0.855 |
| 2013 | $2.923 | $3.012 | 8.9 | 3.0% | $3.922 | $0.910 |
| 2014 | $2.692 | $2.800 | 10.8 | 4.0% | $3.825 | $1.025 |
| 2015 | $1.542 | $1.659 | 11.7 | 7.6% | $2.707 | $1.048 |
| 2016 | $1.286 | $1.355 | 6.9 | 5.4% | $2.304 | $0.949 |
| 2017 | $1.577 | $1.656 | 7.9 | 5.0% | $2.650 | $0.994 |
| 2018 | $2.064 | $2.102 | 3.8 | 1.8% | $3.178 | $1.076 |
| 2019 | $1.916 | $1.940 | 2.4 | 1.3% | $3.056 | $1.116 |
| 2020 | $1.199 | $1.246 | 4.7 | 3.9% | $2.551 | $1.305 |
| 2021 | $1.914 | $2.069 | 15.5 | 8.1% | $3.287 | $1.218 |
| 2022 | $3.565 | $3.720 | 15.5 | 4.3% | $4.989 | $1.269 |
| 2023 | $2.677 | $2.831 | 15.4 | 5.8% | $4.214 | $1.383 |
| 2024 | $2.292 | $2.426 | 13.4 | 5.8% | $3.760 | $1.334 |
| 2025 | $2.206 | $2.329 | 12.3 | 5.6% | $3.660 | $1.331 |
Series: EER_EPD2F_PF4_Y35NY_DPG, EER_EPD2DXL0_PF4_Y35NY_DPG and EMD_EPD2D_PTE_NUS_DPG, EIA annual averages, checked October 23, 2026 (data through 2025). The ULSD series begins in June 2006, so 2006 is omitted as a part year. Simple average of the premium: 9.6 cents.
The grade premium is small and unsteady: it ran from 2.4 cents in 2019 to 15.5 cents in 2021 and 2022, and from 1.3 to 8.1 percent of the heating oil price. Every year from 2021 to 2025 is above 12 cents, while 2016 to 2019 are all under 8. The retail layer in the last column grew over the period: it was $0.733 a gallon in 2007 and $1.331 in 2025, and even the largest wholesale grade premium on record here is small against it. A household shopping between a heating-grade and a road-grade wholesale price is choosing between differences of a few cents, while the delivery and retail stack is a dollar or more.
The gap that stopped moving
The weekly series shows something unusual in the recent record. From the week ending July 25, 2025 through April 10, 2026, a run of 38 consecutive weeks, the premium of ULSD over heating oil stayed between 14.5 and 14.8 cents. An earlier stretch, from mid-March to early June 2025, held between 9.7 and 10.5 cents for 13 weeks. In 2024 the weekly premium swung between 5.5 and 49.9 cents. Two grades that are traded and assessed independently rarely hold a gap that tight, so the long flat runs look more like an assessed differential that is revised from time to time than the day-to-day result of two markets clearing. PetroEyes did not find an EIA explanation and does not claim one. When doing precise work, treat the heating oil spot series with that caution and use the ULSD series as the market signal.
Table 7. Latest six weeks of the New York Harbor spot gap, dollars per gallon
| Week ending | No. 2 heating oil spot | ULSD spot | Gap (cents) |
|---|---|---|---|
| 09/11/26 | $4.802 | $4.928 | 12.6 |
| 09/18/26 | $5.025 | $5.223 | 19.8 |
| 09/25/26 | $4.745 | $4.955 | 21.0 |
| 10/02/26 | $4.661 | $4.871 | 21.0 |
| 10/09/26 | $4.567 | $4.911 | 34.4 |
| 10/16/26 | $4.762 | $5.027 | 26.5 |
Series EER_EPD2F_PF4_Y35NY_DPG and EER_EPD2DXL0_PF4_Y35NY_DPG, weekly, release of October 21, 2026, checked October 23, 2026. The plateau from July 25, 2025 to April 10, 2026 and the 2024 range are computed from the full weekly histories on the same dates.
The gap widened to 34.4 cents for the week ending October 9, the widest in the run shown, as ultra-low-sulfur diesel stayed near $4.91 while heating oil softened. A winter delivery in a household that burns the EIA’s 402-gallon national winter average is shown in the next table, to put the wholesale gap in household dollars.
Table 8. What the wholesale grade gap is worth on a 402-gallon winter
| Gap used | Cents per gallon | Dollars on 402 gallons |
|---|---|---|
| Long-run average, 2007 to 2025 | 9.6 | $38 |
| Plateau, July 2025 to April 2026 | 14.7 | $59 |
| Week ending 10/16/26 | 26.5 | $107 |
| Retail layer, 2025 (retail diesel minus ULSD spot) | 133.1 | $535 |
| Retail premium today (residential minus wholesale heating oil) | 86.7 | $349 |
402 gallons is the EIA Winter Fuels Outlook 2026-27 base case for the average U.S. heating oil household, November to March (checked October 23, 2026). The last two rows compare the grade gap with dealer-level costs; they are not the same quantity as the grade gap.
Which fuel in which equipment: a decision table
The rules above settle most of the common questions, and where they do not settle one, the answer is a manufacturer’s manual and not a general article. Each row names what the sources reviewed here say. None is an instruction to buy or use anything.
Table 9. Common cross-use questions and what the rules say
| Situation | Tax and legal position | Specification position | Who decides the rest |
|---|---|---|---|
| Red-dyed heating oil in a pickup or truck on public roads | Dyed fuel is exempt only for nontaxable uses; IRC 6715 penalty applies to taxable use of dyed fuel | No cetane or lubricity promise on a burner-grade ticket; sulfur may exceed 15 ppm outside the states with rules | Not a question of preference; the dye settles it |
| Undyed ULSD in a home furnace or boiler | Undyed diesel used for home heating is listed by IRS Publication 510 as a nontaxable use a purchaser may claim back | Same boiling range and sulfur or lower; flash point is higher than the heating oil floor | Burner and boiler manufacturer; the tax is paid up front |
| Dyed off-road diesel in a farm tractor or generator | Dyed fuel is intended for exempt off-highway use | Off-road diesel is sold as an engine fuel; the equipment maker states what it needs | Engine maker; seller ticket |
| Dyed ULSD delivered as heating oil to a tank | Normal practice; dye marks the delivery as untaxed for road use | Burner promise on the ticket; ULSD sulfur where the state requires it | Dealer and state regulator |
| Heating oil for a standby generator at a house | IRS Publication 510 lists use in stationary machines, such as generators and compressors, among nontaxable uses for undyed fuel | Generator engines are diesel engines; the engine maker publishes the fuel requirement | Engine manual, then a tax professional |
Sources: IRS Publication 510 (Rev. 12-2025), 26 U.S.C. 6715, EIA Heating oil explained, DieselNet and Maryland COMAR, checked October 23, 2026. This table summarizes rules and does not give tax or engineering advice.
One test sorts almost every row: ask who the fuel is promised to. The dye is a promise to the tax collector that the fuel will not be used on the road, the specification is a promise to the equipment, and the delivery ticket carries both. A mismatch on either side is where problems happen. The weaker instinct, that “it’s all diesel,” is right about chemistry and wrong about the two promises.
Reading a delivery ticket
The same document that tells you the gallons tells you which rulebook the fuel is under. For heating oil, the lines worth reading are the product description (No. 2 heating oil, ULSD, or a bioheat blend), the sulfur grade or ppm figure, whether the fuel is dyed, and the price per gallon with any fuel surcharge shown separately. The EIA’s survey prices exclude taxes, so a ticket that adds a sales or other tax in your state will print higher than the published average. The Winter Fuels Outlook says wholesale heating oil changes reach retail in about four to six weeks, so a ticket from early winter may reflect a wholesale move from October. The gallons-per-house guide and the Winter Fuels Outlook guide are the next step for estimating how many of those gallons you will need.
Questions about heating oil and diesel
Is heating oil the same as diesel fuel?
Both are No. 2 middle distillate from the same refining step, and the EIA calls them closely related products. Treating them as the same product is wrong in practice: highway diesel is made to the ASTM D975 specification with a 15 ppm sulfur ceiling and a cetane minimum, heating oil is made to the ASTM D396 burner specification and is dyed red, and the tax treatment differs by $0.243 a gallon federally before any state tax.
Can you put heating oil in a diesel truck?
Not legally on a public road. The EIA states that the IRS requires heating oil to be dyed red and that red-dyed fuel is illegal to use in vehicles that normally operate on roadways. Under Internal Revenue Code section 6715 the penalty on each act is the greater of $1,000 or $10 for each gallon of dyed fuel involved, in addition to any tax. The mechanical question is separate: the heating oil specification the sources reviewed here has no cetane or lubricity minimum of its own, which diesel engines are built around.
Can you burn diesel fuel in an oil furnace?
Tax law allows it. IRS Publication 510 lists undyed diesel used for home heating, lighting and cooking among the nontaxable uses for which an ultimate purchaser can claim a credit or refund, because the fuel is taxed when sold undyed. Whether a particular burner is approved for it is a different question that belongs to the burner manual, the manufacturer and the installer, and the fuel will have been sold at the taxed price unless you buy dyed fuel.
Why is diesel usually a few cents higher than heating oil at the wholesale level?
The New York Harbor ultra-low-sulfur diesel spot price has averaged 9.6 cents a gallon above the No. 2 heating oil spot price over 2007 to 2025 in the EIA annual series, with a range from 2.4 cents in 2019 to 15.5 cents in 2021 and 2022. The premium is a spot-grade difference, and it is a small part of what a household pays: retail heating oil adds a dealer margin and delivery cost on top of whichever wholesale grade the dealer buys.
What does the red dye actually do?
It marks fuel as untaxed for road use. Treasury Regulation 48.4082-1 requires Solvent Red 164 at a concentration spectrally equivalent to at least 3.9 pounds of Solvent Red 26 per thousand barrels of fuel, which works out to about 42 milligrams of dye solid per gallon. The dye changes the tax status, not the chemistry. EPA says it no longer requires diesel to be dyed at the refinery gate after June 1, 2010, and that the IRS requires untaxed diesel, including heating oil, to be dyed before leaving the terminal.
Does heating oil have to be ultra-low sulfur?
Not under the federal highway and nonroad diesel rules, which DieselNet summarizes as exempting heating oil from the 15 ppm requirement. The requirement came from states instead: the EIA lists New York in 2012, Delaware and New Jersey in 2016, and the six New England states on July 1, 2018. Maryland's regulation sets 0.0015 percent sulfur for fuel oil from July 1, 2019. Check the delivery ticket, because other states may still allow higher sulfur.
Data and sources: U.S. Energy Information Administration, Spot Prices, weekly series EER_EPD2F_PF4_Y35NY_DPG (New York Harbor No. 2 heating oil) and EER_EPD2DXL0_PF4_Y35NY_DPG (New York Harbor ULSD), annual and weekly histories, release of October 21, 2026, checked October 23, 2026. EIA, Heating Oil and Propane Update, week of October 19, 2026 (series W_EPD2F_PWR_NUS_DPG and W_EPD2F_PRS_NUS_DPG; distillate stocks 104.3 million barrels, production 5.232 and demand 3.732 million barrels a day, week of October 16), checked October 23, 2026. EIA, Weekly Retail Gasoline and Diesel Prices (series EMD_EPD2D_PTE_NUS_DPG, annual and weekly), checked October 23, 2026. EIA, Heating oil explained, Diesel fuel explained and British thermal units, checked October 23, 2026 (dye and tax statement; state ULSHO dates; 11 to 12 gallons of diesel per barrel; Btu per gallon). EIA, Winter Fuels Outlook 2026-27, released October 6, 2026 (402 gallons; four-to-six-week pass-through), checked October 23, 2026. Internal Revenue Service, Publication 510, Excise Taxes, Rev. December 2025, checked October 23, 2026. 26 CFR 48.4082-1 via eCFR, checked October 23, 2026. 26 U.S.C. 6715 via Cornell Legal Information Institute, checked October 23, 2026. U.S. Environmental Protection Agency, Diesel fuel standards and rulemakings and its archived compliance help page on dye requirements after June 1, 2010 (19january2021snapshot.epa.gov), checked October 23, 2026. DieselNet, Fuels: USA Diesel Fuel, checked October 23, 2026. ALS Global, ASTM Fuel Specification Overview, checked October 23, 2026. Maryland Division of State Documents, COMAR 03.03.05.04, checked October 23, 2026. ASTM D975 and D396 were not retrievable from ASTM directly, so their values are as reported by the secondary sources named above. All differences, averages, penalties, per-Btu prices and household dollars are arithmetic by PetroEyes on those inputs.