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The control group was working at the commander’s camp and was not exposed to oil or dis 
persants. Cases of injuries and irritation to eyes, impact on consciousness and mucous 
membranes were the most frequently reported symptoms among the control group and were 
higher than the complaint rate from workers on shrimp boats. 
The specific clean-up activities with their different exposure situations show different symp 
tom pattern. Wildlife clean-up workers had the highest risk for health effects followed by 
workers involved in the dispersant use. 
The long-term human health effects of the Deepwater Horizon oil spill are of high interest and 
are under evaluation when this report is written. The GULF-study enrolled over 32,000 partic 
ipants, 75 % were oil spill clean-up workers. The majority (83 %) were residents from the gulf 
coast. The study will consider the health effects of different exposure scenarios during 50 to 
60 different activities of these persons (U.S. Department of Health and Human Services). 
Unfortunately, the study started more than one year after the spill. Such long time frame is 
problematic regarding retrospective quantification of exposure and acute health effects. To 
day, data are not available, because the clinical examination were scheduled to end January 
2016. 
During the time of the health hazard evaluations, NIOSH also conducted exposure meas 
urements during different clean-up activities. A widespread number of oil and dispersant 
components as well as gases and particulate matter were measured. The substances' con 
centrations lay below either detection limits or occupational exposure limits. 
NIOSH reported on some cases where samplers were saturated, maybe due to high humidity 
and thus any quantification was not possible. Only few Carbon Monoxide measurements on 
vessels showed significant levels. But the values could be explained by the exhaust from the 
boats' engines. NIOSH already denied that a full assessment of the real exposure would 
become possible. 
Summary and Outlook 
Acute health effects of oil and oil-dispersant mixtures are similar and depend on the constitu 
ents of the oil spilled. Irritation to eyes, skin, mucous membranes and respiratory tract as well 
as headache were reported after the Prestige as well as after the Deepwater Horizon oil spill. 
Orthopedic symptoms and injuries are the consequence of physical work; injuries are often 
resulting from wild-life cleaning. But the impact on consciousness, headache and irritation to 
eyes could also lead to a higher risk for injuries when dispersants are not used. The impact 
on psychic health seems to be specific for residents of the affected area but will be inde 
pendent from whether or not dispersants are used. 
The use of dispersants results in specific clean-up activities which are not common when oil 
is recovered mechanically; for example, the application and monitoring of dispersants by 
vessels on sea. On the one hand, the risk for beach clean-up workers will change due to the 
exposure to the aerosolized mixture instead exposure to the vapour of oil components. On 
the other hand, there will be a lower demand for onshore workers when using dispersants 
and thus fewer people will be exposed. 
Because of the extensive use of the product during the Deepwater Horizon accident, acute 
toxic effects of COREXIT© 9500 were investigated in animal studies. The studies may show 
probable target effects, like pulmonary, cardiac or neurotoxic effects. But unlike the exposure 
scenarios of the oil spill clean-up workers, the animal studies are limited to acute or subacute 
exposure. No information exists about the documentation of health-related long-term effects