What Are the Potential Physical Health Effects From the Gulf Oil Spill?

An Expert Interview With Vikas Kapil, DO, MPH, From the US Centers for Disease Control and Prevention

Janet Kim, MPH


July 23, 2010

Editor's Note:

The oil spill in the Gulf of Mexico that began on April 20, 2010, when an oil rig exploded in Louisiana, killing 11 workers, is now the worst US environmental disaster. The amount of oil that gushed into the Gulf since then could be as high as 60,000 barrels a day. Various measures to cap and stop the flow had been unsuccessful until July 15, when the oil leak was observed to have stopped after a new containment cap was completely installed on July 12. Also on July 15, a well integrity test was implemented to measure pressure within the oil well and to determine whether the new cap will successfully hold back the flow of oil or prevent a new leak from forming elsewhere. At the time of this interview, the results of the test remain uncertain.

Regardless, the impact to the local ecosystem and to the livelihoods of residents in the affected Gulf states continues to worsen. Detrimental health effects are being observed in the animal and marine life; the body of water of the Gulf itself remains contaminated by an estimated current volume of 90-180 million gallons of oil; oil and tar balls have been washing up on the shores; and volatile organic compounds (VOCs) are still being released into the surrounding ambient air.

The methods used for cleaning up the oil, such as the application of dispersants and burning the oil, are also presenting challenges, introducing new exposures from other chemical pollutants and from particulate matter (PM).

A significant growing concern is how the health of coastal residents and response workers involved with the cleanup efforts could be affected over the short and long term.

At the request of the US Department of Health & Human Services, the Institute of Medicine (IOM) quickly convened a workshop, "Assessing the Human Health Effects of the Gulf of Mexico Oil Spill," on June 22 and 23 in New Orleans, Louisiana. Experts in attendance agreed that existing research that evaluated the adverse health effects for humans from previous oil spills is surprisingly lacking; many of these studies were small, used poor methodology, or focused on short-term health outcomes only.

The US Centers for Disease Control and Prevention (CDC) has published a collection of content updated daily for health professionals, coastal residents, response workers, and the general public that is devoted to this disaster on their Website, CDC: 2010 Gulf of Mexico Oil Spill. Vikas Kapil, DO, MPH, is the Associate Director for Science for the Deepwater Horizon Oil Spill Response at the CDC in Atlanta, Georgia. Dr. Kapil spoke with Medscape about the potential physical health effects in humans who are exposed to an oil disaster and what clinicians can do in response to such situations.

Medscape: What are the potential hazardous substances related to the oil spill itself as well as its cleanup, and what are their specific effects on human health?

Dr. Kapil: The recent Gulf of Mexico oil spill more likely presents a risk for adverse ecologic impact rather than severe adverse human health effects. However, depending on the exposure, the potential exists for human health effects.

On the basis of data from oil recovered from other wells in this area, we expect that the more hazardous substances found in crude oil, such as benzene and sulfides, will make up less than 1% of this oil spill.

Workers at the site of the spill may be more at risk of being exposed to the VOCs, such as benzene or toluene, that are present in crude oil. This guides the National Institute for Occupational Safety and Health's (NIOSH's) recommendations on personal protective equipment for workers. Oil spill workers may need to wear personal protective equipment on the basis of the particular cleanup duties that they perform. The NIOSH Website has more information about their ongoing efforts to protect the health and safety of response workers.

Many of the VOCs have largely evaporated from the weathered oil that reaches the shore, so they present less of a risk for the general public and for those working onshore.

The crude oil involved in this oil spill is called medium sweet crude. "Sweet" means that the oil contains fewer sulfur compounds and is therefore less toxic than other forms of crude oil. Medium crude generally has fewer VOCs and fewer chemicals known to pose long-term health risks compared with other oil types.

One method being used to reduce the amount of oil before it arrives on the shores of the Gulf of Mexico is to burn it. Burning oil may generate PM. PM includes a mix of very small airborne particles and liquid droplets. PM varies in size; some of the smaller PM can be inhaled and deposited in the lung.

Because intentional burning is being conducted far offshore, it is unlikely to reach inhabited areas of the coast. In situ burning is monitored by the US Coast Guard for safe operational practices. As crews burn spilled oil, they carefully watch the weather, wind, and water conditions and monitor the air. If any problems are encountered, oil burning is stopped immediately. The CDC and the Agency for Toxic Substances and Disease Registry (ATSDR) are monitoring the air sampling results to help guide public health decisions. Up-to-date information about the public health effects of burning oil can be found on the CDC Website.

If PM does make it to the shore, it may pose a greater risk for people with underlying health conditions, such as asthma, chronic obstructive pulmonary disease, or heart disease.

People in the area who smell or see smoke may take certain steps to protect themselves:

  • They can choose to leave the area. Those at greatest risk of breathing smoke should evacuate.

  • They can limit their exposure to smoke by remaining indoors and using an air conditioner to filter the air. If available, air conditioning units should be set to "recirculation mode." Those without access to an air conditioner may wish to evacuate until the smoke is completely gone.

  • They should refrain from physical exertion. Physical activity that places extra demands on the lungs and heart -- exercise or physical chores, indoors or outdoors -- should be kept to a minimum.

Dust masks, bandanas, or other cloths -- even if wet -- will not protect against smoke inhalation.

The oil spill is not expected to affect any municipal water supplies. If people have concerns about the quality of their water, they should contact their local water utility.

The US Environmental Protection Agency (EPA) is monitoring the air quality in the region. Maps and charts at https://gulfcoast.airnowtech.org show current ozone and fine particulate Air Quality Index values that are being measured by air quality monitors located along the Gulf Coast. These maps and charts are updated hourly to show the most recent conditions.

Oil spill response workers may be exposed to many different chemical and physical hazards. The risk for each type of exposure depends on the type and location of the oil spill, the type and stage of response, and the workers' specific tasks.

Chemical exposures may include:

  • Benzene, toluene, ethylbenzene, xylenes, and other VOCs;

  • Oil mist; or

  • Naphthalene and other polycyclic aromatic hydrocarbons.

More information about these chemicals is available on the CDC [CDC: Facts About Benzene] and ATSDR Websites [ATSDR: ToxFAQsTM for Benzene; ATSDR: ToxFAQsTM for Polycyclic Aromatic Hydrocarbons (PAHs)].

Physical hazards may include:

  • Heat stress due to the high temperatures and humidity;

  • Ergonomic hazards that can cause injury to the musculoskeletal system;

  • High noise levels;

  • Sun exposure and dehydration; and

  • Injuries due to slips, trips, and falls on slippery walking and working surfaces.

Other safety hazards may come from the use of tools, equipment, machinery, and vehicle operations near workers.

The dispersants used in the oil spill have been COREXIT® 9500 and 9527 [Nalco Company; Naperville, Ill]. Both will begin to break down once applied to the oil slick. In aquatic environments, each will break down within 16 days. Exposures to dispersants will most likely occur among workers applying the material.

Health effects that could be experienced are dependent on the extent of exposure to the dispersants and may include:

  • Defatting and drying of the skin and possibly dermatitis, as a result of prolonged contact with the skin;

  • Chemical pneumonitis, if aspirated into the lungs;

  • Respiratory irritation as a result of repeated and prolonged inhalation exposure to vapor; and

  • Eye irritation as a result of repeated and prolonged exposure.

Repeated or excessive inhalation exposure to dispersants may lead to nausea, vomiting, hemolysis, renal or hepatic injury, metallic taste, central nervous system depression, or anesthetic or narcotic effects. 2-Butoxyethanol, a component of one of the dispersants, has not been classified as to its carcinogenicity. For most people brief contact with a small amount of oil dispersants presents no harm.

Employers should train oil spill response workers about their potential hazards and safe work practices to prevent and control these risks.

If healthcare professionals require additional, specific information about a particular case, they can call their local poison control center at 1-800-222-1222.

Medscape: What is the CDC doing to monitor or track the potential human health effects in the areas affected?

Dr. Kapil: The CDC and the US Department of Health & Human Services recognize the importance of anticipating, monitoring, and responding to any potential public health hazards that may affect human health. Currently, over 300 CDC and ATSDR staff members are involved in the response, including a number of staff members deployed to Gulf Coast states.

The CDC, along with state and local health departments, is conducting surveillance across the 5 Gulf states for health effects possibly related to the oil spill using national and state-based surveillance systems, including the National Poison Data System (NPDS) and BioSense. These surveillance systems track symptoms related to the eyes; skin; and respiratory, cardiovascular, gastrointestinal, and neurologic systems of exposed persons. This tracking effort also includes collecting data on persons with worsening of asthma or those with cough, chest pain, eye irritation, nausea, and/or headache. If these surveillance systems identify groups of people with these symptoms, state and local public health officials will be able to follow up as needed to investigate whether an association is present between the symptoms and the oil spill. This follow-up is important because the same symptoms could be related to a different cause.

NIOSH is working to protect workers and volunteers from potential safety and health hazards related to the spill and cleanup efforts. The CDC is sharing its health information with industry, the Occupational Safety & Health Administration (OSHA), the US Coast Guard, and other federal and state agencies. NIOSH is also helping OSHA and the National Institute of Environmental Health Sciences (NIEHS) by providing technical assistance for training response workers.

Furthermore, NIOSH is collaborating with British Petroleum (BP) Safety and OSHA compliance personnel to coordinate the collection and analysis of injury and illness data that BP are reporting to OSHA. NIOSH is also establishing a voluntary roster of workers participating in the response to create a record and a mechanism to contact these workers about spill-related symptoms of illness or injury, if it becomes necessary. More than 45,000 responders -- BP-trained, volunteer, vessel of opportunity operators, and federal workers -- have been added to the roster. Workers are entered into the roster through a voluntary system at the staging areas to which workers report daily and during worker training, and through an electronic version of the form that is posted on a secure Website; NIOSH has provided the link to multiple federal agencies and BP, and has asked them to refer workers to the Website to complete the roster form electronically.

A CDC team of environmental health experts continues to review environmental data packages in coordination with the EPA. CDC scientists are reviewing these data to determine whether exposure to oil, oil constituents, or dispersants might cause potential short- or long-term health effects. These data include sampling results for air, water, and soil/sediment as well as waste oil samples, which are material actually reaching the beaches or marshes.

Some of the pollutants that have been reported may cause temporary eye, nose, or throat irritation; nausea; or headaches, but scientists believe that levels are not high enough to cause long-term harm.

The EPA and CDC will continue to monitor the air, water, and soil/sediment. If we begin to find levels that may be of health concern, we will update the public. The latest information on air quality and monitoring data along the Gulf Coast is available on the EPA and Data.gov Websites.


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