The U.S. Coast Guard monitors all oil carriers within United States 

 waters to assure that they comply with Federal regulations. They must 

 have and maintain modern navigational equipment. No discharges of bilge 

 wastes, ballast water, or other polluted water are allowed within 50 miles 

 of shore. Enforcement of these and other standards have been only partially 

 successful [167]. The Coast Guard and other Federal agencies have 

 developed regional plans for cleanup following oil spills. 



Most oil spilled into water initially floats at the surface. However, 

 wind and water forces effectively distribute spilled petroleum hydro- 

 carbons into all components of the marine and coastal environment, includ- 

 ing the water column, sediments, and the atmosphere. 



4.19.2 Oil Tankers 



World tanker tonnage has increased four fold in 12 years. At the 

 beginning of 1976, Commerce Department figures show there were 5,311 

 tankers in the world, with a total bulk of 302.3 million tons [168]. 



Tankers vary in size from 10,000 tons to 500,000 tons (see 

 Table 29). Smaller vessels are used to make short runs in congested 



coastal areas. Most new ships are giant supertankers (e.g. 200,000 tons 

 or more) which are more economical on long trips. However, the larger 

 ships have too deep a draft to navigate in most American harbors and 

 must be moored offshore, necessitating additional transfer to pipeline 

 or small tankers to move the oil ashore. 



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