Pollution effects from tanker spills are related in size and 

 frequency to a number of variables. Vessel age, design, degree of 

 compartmentalization (number of oil storage tanks in a ship), and 

 prevailing weather conditions are directly related to the frequency and 

 magnitude of oil spills. Other factors are the regulations governing 

 operations in severe weather, the size of the tanker, and the nation of 

 tanker registry. Human factors include the degree of a crew's operational 

 experience in particular waters and harbors, the degree and quality of 

 their training, and the nature of their operations. The types of 

 accidents that release oil and the percent of the total volume of spilled 

 oil that was caused by each type are shown in Figure 50. 



Figure 50. Type, number (in parentheses) and percentage of the polluting 

 incidents resulting from tanker accidents (Source: Reference 169). 



189 



