Tuesday, August 17, 2010
From the Journal of American Medical Association...
Health Effects of the Gulf Oil Spill
JAMA. Published online August 16, 2010. doi:10.1001/jama.2010.1254
The oil spill in the Gulf of Mexico poses direct threats to human health from inhalation or dermal contact with the oil and dispersant chemicals, and indirect threats to seafood safety and mental health. Physicians should be familiar with health effects from oil spills to appropriately advise, diagnose, and treat patients who live and work along the Gulf Coast or wherever a major oil spill occurs.
The main components of crude oil are aliphatic and aromatic hydrocarbons.1 Lower-molecular-weight aromatics—such as benzene, toluene, and xylene—are volatile organic compounds (VOCs) and evaporate within hours after the oil reaches the surface. Volatile organic compounds can cause respiratory irritation and central nervous system (CNS) depression. Benzene is known to cause leukemia in humans, and toluene is a recognized teratogen at high doses.1 Higher-molecular-weight chemicals such as naphthalene evaporate more slowly. Naphthalene is listed by the National Toxicology Program as "reasonably anticipated to cause cancer in humans" based on olfactory neuroblastomas, nasal tumors, and lung cancers in animals.2 Oil can also release hydrogen sulfide gas and contains traces of heavy metals, as well as nonvolatile polycyclic aromatic hydrocarbons (PAHs) that can contaminate the food chain. Hydrogen sulfide gas is neurotoxic and has been linked to both acute and chronic CNS effects; PAHs include mutagens and probable carcinogens.1 Burning oil generates particulate matter, which is associated with cardiac and respiratory symptoms and premature mortality. The Gulf oil spill is unique because of the large-scale use of dispersants to break up the oil slick. By late July, more than 1.8 million gallons of dispersant had been applied in the Gulf. Dispersants contain detergents, surfactants, and petroleum distillates, including respiratory irritants such as 2-butoxyethanol, propylene glycol, and sulfonic acid salts.
Acute Health Effects From Oil and Dispersants
In Louisiana in the early months of the oil spill, more than 300 individuals, three-fourths of whom were cleanup workers, sought medical care for constitutional symptoms such as headaches, dizziness, nausea, vomiting, cough, respiratory distress, and chest pain. These symptoms are typical of acute exposure to hydrocarbons or hydrogen sulfide, but it is difficult to clinically distinguish toxic symptoms from other common illnesses.1
The US Environmental Protection Agency (EPA) set up an air monitoring network to test for VOCs, particulate matter, hydrogen sulfide, and naphthalene. A Centers for Disease Control and Prevention analysis of the EPA data concluded: "The levels of some of the pollutants that have been reported to date may cause temporary eye, nose, or throat irritation, nausea, or headaches, but are not thought to be high enough to cause long-term harm."3 Data posted on BP's Web site suggest that air quality for workers offshore is worse than on land. Local temperatures pose a risk of heat-related illness, which is exacerbated by wearing coveralls and respirators, implying a trade-off between protection from chemical hazards and heat.
Skin contact with oil and dispersants causes defatting, resulting in dermatitis and secondary skin infections. Some individuals may develop a dermal hypersensitivity reaction, erythema, edema, burning sensations, or a follicular rash. Some hydrocarbons are phototoxic.
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