Crude oil is toxic to humans. Short- term and long-term health risks from exposure to oil exist, but is cancer included in these risks? Indeed, oil has compounds linked to cancer, although diagnosis generally occurs years after exposure.
Cancer risk from oil exposure can be divided into two categories: the risk for workers involved in clean-up, and potential risk to the general public including consumption of contaminated food supply.
Risks to the clean-up workers:
Clean-up workers are most intimately exposed to inhaling and ingesting oil. That is, breathing it in and actually swallowing small particles. Workers actually breathe in oil and its by-products from burning. As well, varying amounts can get absorbed into their skin and get into their mouth directly from oil on hands and fingernails and small amounts on food. While workers with the most direct exposure have the greatest cancer risk, oil can also enter lungs as a mist or be absorbed through the skin of workers hosing down contaminated beaches.
A few of the toxic components of crude oil include benzene, toluene and polycyclic aromatic hydrocarbons. Crude oil also contains mercury and lead. The level of risk associated with each of these depends on dose and length of exposure. While learnings of cancer risk from exposure to combinations of these components could have come from the Exxon Valdez oil spill, little data exist to draw from. Thus, little is truly known about the cancer effects of simultaneous exposure to the many components of oil.
What is known are the cancer risks due to the individual components listed above. Benzene exposure links to leukemia, particularly acute myeloid leukemia (AML) and to a lesser degree, chronic lymphocytic leukemia (CLL). (read more) Leukemia is a cancer of blood-forming cells in the bone marrow. While some address toluene as causing cancer, the Department of Health and Human Service’s Agency for Toxic Substance and Disease Registry (ATSDR) reports that toluene is not thought to cause human cancer.
Polycyclic aromatic hydrocarbons (PAHs) are a group of over 100 different chemicals formed during incomplete burning of oil. The ATSDR states that some PAHs cause cancer. Breathing or touching mixtures of PAHs over periods of time lead to lung cancer, stomach cancer, and skin cancer. (read more) International researchers report heavier exposure to PAHs entails greater risk for cancer, most notably of the lung, skin, and bladder. (read more)
Mercury may or may not be related to cancer. Differing forms of mercury exist with different cancer potential. (read more on mercury) According to the American Cancer Society, weak evidence loosely links lead exposure with cancers of the lung and stomach, and even more weakly to brain and kidney cancers.
Risks to general public:
The cancer risks to the general public due to the oil spill are thought to be quite low. (read more) The greatest cancer risks from oil and its by-products along the shoreline include lung cancer and skin cancer. Avoiding these areas and avoiding touching of all oil and by-products are the best forms of cancer prevention.
As for the food supply, the main line of defense involves closing fisheries in the spill’s path including those within a buffer around the known location of the spill. The Director of Tulane University’s Center for Applied Environmental Public Health reports that oil contaminants would break down in the body and be excreted leaving “little chance of getting cancer from tainted seafood even if people ate it for many years”. Yet the National Oceanic and Atmospheric Association (NOAA) and the U.S. Food and Drug Administration have shut down fisheries. Further, NOAA created and deployed a seafood sampling and inspection plan for commercial and recreational sea food sources looking for signs that contamination has spread beyond the known affected areas. Sampling also provides benchmarks enabling the tracking of any increases in contaminant levels once fishing is allowed to resume.
The imminent issues of stopping the oil spillage and addressing short-term health effects among workers remain, yet longer-term risks including uncertainty of the level of increased cancer risk loom. Prevention of these longer term risks requires prevention now.
For more information, the EPA website has updates on the spill in both English and Spanish. Click here to go to the EPA’s questions and answers section. The NOAA website is another source of updated information and fact sheets.