Types of Oil

thin layer of oil on surface of water
Oil sheen on surface mid-ship at the WWII Valor in the Pacific National Monument

NPS Photo

Not all oil spills are the same. There are several types of oil and when a spill occurs they affect the land and water in different ways. They are categorized as follows:

Group 1: Gasoline Products

  • Very volatile and highly flammable

  • Highly acute toxicity to organisms

Group 2: Diesel-Like Products/Light Crude Oils

  • Diesel fuel, home heating oil, jet fuels, kerosene

  • Spread rapidly into thin slicks

  • Moderate to high acute toxicity to organisms

Group 3: Medium Crude Oils/Intermediate Products

  • Moderately volatile

  • For crude oils, up to one-third will evaporate in the first 24 hours

  • Stranded oil tends to smother organisms

gloved hands holding jar of thick and sludge-like oil
An oil sample was taken by a NPS Law Enforcement Ranger on Alcatraz.

NPS Photo

Group 4: Heavy Crude Oils/Residual Products

  • Very little product loss by evaporation

  • Can be very sticky

  • Stranded oil tends to smother organisms

Group 5: Non-floating Oils

  • Very heavy fuel oils

  • Oftentimes will initially float, then be more likely to submerge

Last updated: June 13, 2017


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