TYPES AND CHARACTERISTICS OF 

 OILS AND HAZARDOUS CHEMICALS 



Comdr. Fred Halvorsen 



Marine Safety School 



U.S. Coast Guard Reserve Training Center 



Yorktown, Virginia 



OILS 



We are all reasonably familiar with the properties of oil when spilled 

 on water. Oil is normally insoluble in water, less dense than water, and 

 persists in the environment for some time as an identifiable material. Oils 

 may be of mineral origin (such as crude oil), of vegetable origin (such as 

 palm oil), or of animal origin (such as tallow). Chemically, "oils" may be 

 composed of hundreds of various chemical compunds, which may be liquids, 

 solids, and gases dissolved in a homogeneous liquid. Oil may be "thin" and 

 spread rapidly over the water's surface or be "thick" and coagulate in so- 

 called pancakes. Some oils must be heated to allow them to be pumped and 

 when they are spilled on water, will adhere together into "tar balls" which 

 persist for months as pieces of asphalt-like materials in the oceans. While 

 most oils float, some oils have densities near that of water. If cold, the 

 oil may have a density greater than that of water and sink. As the water 

 temperature increases, the oil may become neutrally buoyant and then float. 

 Such an appearance of an oil in the spring, after an oil spill which appeared 

 minimal in the winter, can cause quite a bit of excitement. 



Oils in transportation are classed as flammable or combustible liquids. 

 Flammable liquids are those liquids whose vapors can be readily ignited at 

 room temperatures. Combustible liquids are those liquids which must be heated 

 before the vapors can be ignited. When in marine transportation in bulk 

 quantities by tank vessel, oils are regulated by the U.S. Coast Guard, under 

 46 Code of Federal Regulations (CFR) 30 to 40, Subchapter D, Tank Vessels. 

 Such tank vessels are designed primarily to prevent or reduce the possibility 

 of ignition of the flammable or combustible vapors above the oil cargo and 

 prevent the release of the oil to the environment. The vapors given off by 

 oils may not only be flammable or comustible, but also may be toxic, irritat- 

 ing, anesthetic, or a combination thereof. Crude oils, in particular, contain 

 many gases which can be, if not unpleasant smelling, injurious, or fatal when 

 inhaled. "Sour" crudes contain hydrogen sulphide gas, whose toxic properties 

 parallel those of hydrogen cyanide gas. Some oils, notably crudes and 



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