Heavy Fuel Oil No. 6 (Bunker C)
Heavy fuel oil No. 6, also known as Bunker C, is a high-viscosity residual fuel oil with a Saybolt Universal viscosity at 37.8°C exceeding 125 seconds and API gravity of 25 degrees or more, containing biodiesel as a blend component. It falls under HTS 2710.20.1050 as a distillate and residual fuel oil used primarily for marine bunkering and large industrial boilers. The biodiesel content ensures classification within this specific subheading for blended preparations.
Import Duty Rates by Country of Origin
Alternative Classifications
This product could be classified differently depending on its characteristics or intended use.
If not containing biodiesel
Blends without biodiesel fall under other petroleum oils and preparations in 2710.19, excluding biodiesel-specific subheadings.
If testing less than 25 degrees A.P.I.
Lower API gravity heavy fuel oils shift to 2710.20.20, separating lighter distillates from heavier residuals.
If considered crude or unrefined
Petroleum oils not refined beyond crude processing remain in Chapter 27 heading 2709, excluding prepared fuel blends.
Not sure which classification is right?
The Tariff Assistant works through the GRI rules on your specific product to reach the right HTS code — and can price the duty on it in the same conversation.
Import Tips & Compliance
• Verify Saybolt viscosity certification at 37.8°C exceeds 125 seconds and API gravity ≥25° using ISO/ASTM methods to confirm HTS 2710.20.1050 classification
• Provide lab analysis reports proving ≥70% petroleum oil content with biodiesel (mono-alkyl esters of fatty acids) to avoid reclassification as waste oils
• Ensure IMO-compliant sulfur content documentation for marine fuels to meet U.S
• EPA import regulations and prevent customs holds
Related Products under HTS 2710.20.10.50
Biodiesel-Blended Residual Fuel Oil IFO 380
IFO 380 is an intermediate fuel oil with viscosity >125 Saybolt seconds at 37.8°C, API ≥25°, blended with biodiesel for marine propulsion. Classified under HTS 2710.20.1050 due to its heavy fuel characteristics and biodiesel incorporation as a basic constituent. Primarily used in shipping vessels requiring high-energy density fuels.
No. 6 Fuel Oil with 20% Biodiesel Blend
A 80/20 blend of No. 6 residual fuel oil and biodiesel, exhibiting Saybolt viscosity >125 sec at 37.8°C and API gravity ≥25°, designed for industrial heating. HTS 2710.20.1050 applies as a biodiesel-containing heavy fuel oil preparation with petroleum as the basic constituent. Common in power plants and large furnaces.
Marine Heavy Fuel Oil MFO 180 Biodiesel Blend
MFO 180 heavy fuel oil blended with biodiesel, meeting >125 Saybolt viscosity at 37.8°C and ≥25° API for ocean-going vessels. Falls under HTS 2710.20.1050 as a biodiesel-containing residual/distillate fuel oil. Provides high calorific value for main engines.
Industrial Boiler Heavy Fuel Oil HFO Biodiesel Mix
HFO for stationary boilers blended with biodiesel, >125 Saybolt sec viscosity at 37.8°C, API ≥25°, used in manufacturing heat processes. HTS 2710.20.1050 covers this as biodiesel-blended heavy fuel preparation with ≥70% petroleum oils. Essential for cement kilns and steel mills.