40 
Gràbsch - Health effects of mineral oil and dispersants 
The different risk of different clean-up worker groups (volunteers, paid workers, fishermen) 
was investigated by Carrasco et al. (2006). Fishermen, who were the poorest informed, suf 
fered the most toxicity problems (perhaps as a consequence of the scant use of masks) and 
constituted the subset among whom the information received was least effective (Carrasco et 
al. 2006). The case of the Prestige showed the importance of a clear risk communication and 
the briefing of the clean-up workers resulting in the use of personal protective equipment and 
a lower risk for oil-mediated health effects. 
Health Effects of Dispersants 
In general, dispersants consist of solvents and surface active agents. The same components 
are found in many dispersant formulas. However, a complete list of all constituents is missing 
for the most dispersants e.g. those listed by EMSA (see references). 
Since the Deepwater Horizon rig explosion and the use of enormous amounts of COREXIT© 
9500 and COREXIT© 9527, the U.S. EPA published the lists of constituents of the COREXIT 
formulas (U.S. EPA). 
The Deepwater Horizon spill is a good case study on dispersant use since the compositions 
of the formulas are available. Therefore, the COREXIT formulas may be taken as an exam 
ple for dispersants in general. 
Some constituents of the COREXIT© formulas are chemicals generally used in consumer 
products. The non-ionic surfactants Span 80®, Tween 80 and propylene glycol are also used 
as food additives (Span 80: E494; Tween: 80 E433; propylene glycol: E1520) and possess a 
low toxicity. The anionic surface active agent dioctyl sodium sulfosuccinate (DOSS) is even 
used as a laxative pharmaceutical. It is general assumed in toxicology that surface active 
agents increase the absorption in the gut. 2-Butoxyethanol is used as solvent with modest 
surfactant properties in household products and cosmetics. In general, it can be stated that 
the main toxic effects of the mentioned substances are irritation to the eyes, the skin and 
mucous membranes. The solvent petroleum distillates possess a higher toxicity compared to 
the other components. The health effects shown in Table 7.2 are those of the single com 
pounds, not their mixtures. 
Material safety data sheets (MSDS) for both products explain skin and eye irritation, but 
slight differences in toxicity exist. The issue of a MSDS is the safe handling of chemicals and 
the description of precautionary measures. Therefore, the risk during the handling of disper 
sants (preparation and turnout of the formulas) is covered but no additional exposure with 
mineral oil is considered.