CHEMICAL OIL DISPERSING AGENTS 

 AND THEIR FEASIBILITY FOR USE 



Gerard P. Canevari 



INTRODUCTION 



Widespread interest in chemical oil dispersing agents first developed 

 after their use during the Torrey Canyon disaster in March 1967. Few areas 

 of technology, however, have been more controversial, more misunderstood, 

 or more politically entangled. In order to put the subject in a proper per- 

 spective and to assess the feasibility of using dispersants, I am going to 

 discuss the early history and current status of chemical oil dispersing agents. 



CONCERNS RELATING TO DISPERSANT USE 



Reluctance to consider chemical dispersion as a viable means of minimizing 

 damage from oil spills was due historically to two major concerns: 



1. Toxicity of chemical dispersants and dispersed oil, and 



2. Effectiveness and practicability of the technique. 



The toxicity of chemical dispersants has been a concern from the begin- 

 ning. In the first widescale use of these dispersants (the Torrey Canyon 

 spill), the materials were, in the true sense, detergents. The formulation 

 consisted of a surface-active agent (surfactant) and a solvent, the latter 

 being somewhat aromatic in order to enhance the "cutting of sludge and waxy 

 deposits in oiled tanks." Although the dispersants were effective in dispers- 

 ing oil with the application of sufficient mixing energy, they would be 

 considered quite toxic by today's standards. 



The toxic aspect was emphasized in a study conducted by Smith (1968) 

 after the Torrey Canyon incident. The study indicated that, in some 

 areas, particularly in the intertidal zone, the chemicals used were more 

 toxic to marine life than the oil itself. This conclusion is supported by 

 the results of a toxicity test conducted by Oda (1968) (Table 1). Products 

 A, B, C, and D are chemicals that were used during the Torrey Canyon inci- 

 dent. The concentrations represent the 96-h TLm.; that is, the chemical 

 concentration required to kill 50 percent of the test species in a 96-h 

 exposure period. Values of 6 to 13 ppm can be considered quite toxic by 

 today's standards. In contrast, the 96-h TLm value for a product 

 developed after the Torrey Canyon incident (Product E) can be greater than 

 10,000 ppm. 



Exxon Research and Engineering Company 

 Florham Park, New Jersey 07932 



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