Oil Types

We think of oil as being a single substance, but there actually are many different kinds of oil. Kinds of oil differ from each other in their viscosity, volatility, and toxicity. Viscosity refers to an oil's resistance to flow. Volatility refers to how quickly the oil evaporates into the air. Toxicity refers to how toxic, or poisonous, the oil is to either people or other organisms.

When spilled, the various types of oil can affect the environment differently. They also differ in how hard they are to clean up. Spill responders group oil into four basic types. Here is a list of those four types, along with a general summary of how each type can affect shorelines.

1. Type 1: Very Light Oils (Jet Fuels, Gasoline)
   • Highly volatile (should evaporate within 1-2 days).
     
   • High concentrations of toxic (soluble) compounds.
     
   • Localized, severe impacts to water column and intertidal resources.
     
   • No cleanup possible.

2. Type 2: Light Oils (Diesel, No. 2 Fuel Oil, Light Crudes)
   • Moderately volatile; will leave residue (up to one-third of spill amount) after a few days.
     
   • Moderate concentrations of toxic (soluble) compounds.
     
   • Will "oil" intertidal resources with long-term contamination potential.
     
   • Cleanup can be very effective.

3. Type 3: Medium Oils (Most Crude Oils)
   • About one-third will evaporate within 24 hours.
     
   • Oil contamination of intertidal areas can be severe and long-term.
     
   • Oil impacts to waterfowl and fur-bearing mammals can be severe.
     
   • Cleanup most effective if conducted quickly.

4. Type 4: Heavy Oils (Heavy Crude Oils, No. 6 Fuel Oil, Bunker C)
   • Heavy oils with little or no evaporation or dissolution.
     
   • Heavy contamination of intertidal areas likely.
     
   • Severe impacts to waterfowl and fur-bearing mammals (coating and ingestion).
     
   • Long-term contamination of sediments possible.
     
   • Weathers very slowly.
     
   • Shoreline cleanup difficult under all conditions.

Back to Prior Page

Oil Spill Scenario Back to the Oil Spill Scenario page.

Tips for Creating Your Own Exercise Back to the Tips for Creating Your Own Exercise page.

More Information More technical information about the characteristics of different oils is available on these fact sheets.

Alaska North Slope Crude Blends (Document format: PDF, size: 611.0 K)

No. 6 Fuel Oil (Bunker C) Spills (Document format: PDF, size: 611.3 K)

Small Diesel Spills (500-5000 gallons) (Document format: PDF, size: 544.5 K)

Tarballs (Document format: PDF, size: 384.2 K)

Other Pages in this Exercise

Using Maps to Evaluate Environmental Tradeoffs The main ESI Exercise page.

Introduction to ESI Maps An explanation of the maps used by oil spill responders to set protection priorities.

Making a Map Kit Instructions for preparing the materials students will need to complete the exercise.

Conducting the Exercise Step-by-step instructions for conducting this exercise.