Fuel Spill Classifications

While all fuel spills are cause for concern, they can have varying impacts and call for different response methods based on the type of fuel spilled. The properties and environmental impacts of spills are influenced by many factors including fuel type, weight, viscosity, temperature, and time. The category of the spill will also determine the technology needed to ensure an effective response.

Type A: Light Volatile Oils

• Type A fuel spills consist of distilled fuels and light crude oils. They are highly fluid and usually transparent, present a strong odor and spread rapidly. Type A fuels are highly flammable and can quickly lose their volatile components due to evaporation. These fuel types are generally considered to be highly toxic to marine or aquatic life.

  Type A fuels can quickly penetrate soil or contaminate water, although they can be rinsed from plants and non-porous surfaces with simple agitation. They also pose the danger of ignition. They require a fast response to minimize environmental impact.

Type B: Non-Sticky Oils

• Type B fuel spills consist of medium to heavy paraffin-based oils, and can contain both refined and crude oils. These are thicker oils of moderate viscosity that can penetrate some looser soils and ground surfaces. They are fluid and float at ambient temperatures, have a waxy or oily feel and can temporarily coat plants and wildlife.

  Type B fuel spills are generally easy to remove from surfaces by low-pressure water flushing, but can cause lasting damage if they contaminate the soil.

Type C: Heavy Sticky Oils

• Type C fuel spills consist of residual fuel oils and mixed-based crude oils, are fluid and float at ambient temperatures. They appear as thick black or brown slicks and will coat plants and wildlife, leading to smothering if not treated. While these types of spills will initially float on water surfaces, they can sink after weathering.

  Type C spills are difficult to remove from surfaces and can interfere with many types of recovery equipment, but do not penetrate most soils so they will tend not to cause lasting, toxic contamination of the environment.

Type D: Non-Fluid Oils

• Type D fuel spills consist of all types of residual and heavy crude oils that float, but do not flow at ambient temperatures. These oils appear as tarry or waxy lumps and can not be pumped without preheating or slurrying. Most conventional cleanup equipment is unable to remove Type D spills from water.

  Type D fuels are initially solid and pose no danger of toxic contamination, but can melt and flow if heated by the sun, causing concerns similar to those of less viscous spill types.

Type E: Sinking Oils

• Type E fuel spills consist of residual, fuel oils and heavy crudes that have become heavily weathered or entrained with sediments. They appear black or brown and may or may not flow, depending on their exact makeup. Sinking oils will either come to rest on the ocean floor or float in a neutrally buoyant layer of water and may form pavements when affected by water temperature and salinity.