May 23

Dr. Michael Harbut, Karmanos Cancer Institute

Dr. Kathleen Burns, Sciencecorps

Many people will be exposed to airborne and waterborne chemicals as a result of the BP Gulf of Mexico spill.  It is important to understand the potential toxic effects and take appropriate steps to prevent or reduce exposure and harm.

Crude Oil Fact Sheet

Crude oil contains hundreds of chemicals, comprised primarily of hydrogen and carbon (e.g., simple straight chain paraffins, aromatic ring structures, naphthenes), with some sulfur, nitrogen, metal, and oxygen compounds (see Table D-1 in CDC, 1999 linked below).  Crude oil composition varies slightly by its source, but its toxic properties are fairly consistent. Chemicals such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very toxic components of crude oil and of high concern.  These and other chemicals are volatile, moving from the oil into air.  Once airborne, they blow over the ocean for miles, reaching communities far from the oil spill.  They can be noticed as petroleum odors. Those working on the spill and people far from it can be exposed to crude oil chemicals in air.

We have prepared 1 page summaries for the public and for workers.  You can download and print them.

Chemicals being applied to the water, such as dispersants, are also of concern.  We don’t have chemical composition details at this time, so can’t provide information on health hazards, beyond noting that most are reported to contain petroleum distillates, which pose health hazards when aspirated.  See EPA’s summary of oil spill response products (March 2010):


Exposure can occur through skin contact, inhalation of contaminated air or soil, and ingestion of contaminated water or food. These can occur simultaneously.  Exposure pathways may result in localized toxicity (e.g., irritation of the skin following contact), but most health effects are systemic because ingredients can move throughout the body.  Exposure varies based on the duration and concentrations in contaminated media. Differences may result from location, work and personal activities, age, diet, use of protective equipment, and other factors.  Concurrent exposure to other toxic chemicals must be considered when evaluating toxic effects. Some chemicals in crude oil are volatile, moving into air easily, and these can often be detectable by smell.

Basic Physiological Effects

Crude oil is a complex mixture of chemicals that have varying abilities to be absorbed into the body through the skin, lungs, and during digestion of food and water. Most components of crude oil enter the bloodstream rapidly when they are inhaled or swallowed. Crude oil contains chemicals that readily penetrate cell walls, damage cell structures, including DNA, and alter the function of the cells and the organs where they are located. Crude oil is toxic, and ingredients can damage every system in the body:

– respiratory
- nervous system, including the brain
- liver
- reproductive/urogenital system
- kidneys
- endocrine system
- circulatory system
- gastrointestinal system
- immune system
- sensory systems
- musculoskeletal system

Damaging or altering these systems causes a wide range of diseases and conditions. In addition, interference with normal growth and development through endocrine disruption and direct damage to fetal tissue is caused by many crude oil ingredients (CDC, 1999). DNA damage can cause cancer and multi-generational birth defects.

Acute Exposure Hazards – brief exposure at relatively high levels[1]

Crude oil contains many chemicals that can irritate the skin and mucous membranes on contact.  Irritant effects can range from slight reddening to burning, swelling (edema), pain,and permanent skin damage.   Commonly reported effects of acute exposure to crude oil through inhalation or ingestion include difficulty breathing, headaches, dizziness, nausea, confusion, and other central nervous system effects. These are more likely to be noticed than potentially more serious effects that don’t have obvious signs and symptoms: lung, liver and kidney damage, infertility, immune system suppression, disruption of hormone levels, blood disorders, mutations, and cancer.

Chronic Exposure Hazards – long-term exposure at relatively low levels

This type of exposure should be avoided, if at all possible, because the potential for serious health damage is substantial.  Chronic health effects are typically evaluated for specific crude oil components (see CDC, 1999), and vary from cancer to permanent neurological damage.  They cover a range of diseases affecting all the organ systems listed above.

Susceptible Subgroups

Children are vulnerable to toxic chemicals in crude oil that disrupt normal growth and development.  Their brains are highly susceptible to many neurotoxic ingredients. Endocrine disruptors in crude oil can cause abnormal growth, infertility, and other health conditions. Children’s exposures may be higher than adults and can include contaminated soil or sand. Newborns are especially vulnerable due to incompletely formed immune and detoxification systems.

Many people with medical conditions are more susceptible to crude oil toxicity because chemical ingredients can damage organ systems that are already impaired. Specific susceptibilities depend on the medical condition (e.g., inhalation poses risks for those with asthma and other respiratory conditions).

People taking medications that reduce their detoxification ability, and those taking acetaminophen, aspirin, haloperidol, who have nutritional deficiencies or who concurrently drink alcohol may be more susceptible. Some inherited enzyme deficiencies also increase susceptibility (listed in CDC, 1999).

People exposed to other toxic chemicals at work or home may be at higher risk.

Pregnancy places increased stress on many organ systems, including the liver, kidneys, and cardiovascular system. Chemicals in crude oil that are toxic to these same systems can pose serious health risks. Pregnancy also requires a careful balance of hormones to maintain a health pregnancy and healthy baby. Endocrine disruptors in crude oil can jeopardize the hormone balance.

The developing fetus is susceptible to the toxic effects of many chemicals in crude oil. Many cause mutations, endocrine disruption, skeletal deformities, and other types of birth defects.

Personal and Public Protection

It is critical that people who work with or around crude oil wear appropriate personal protective equipment such as gloves, masks, respirators, and water repellant clothing, to minimize exposure.  The necessary equipment will depend on the kind of exposure that can occur (dermal, inhalation, ingestion). See OSHA guidance at OSHA 2010 link below. Susceptible members of the public require notice when exposure may occur (e.g., when contaminated air masses move inland) so they can take protective actions.


CDC, 1999:

OSHA, 2010:

NLM: – very limited information on human health

The National Toxicology Program (NIEHS-NIH) provides information on carcinogenic crude oil ingredients (e.g., benzene) & limited information on reproductive hazards

California’s EPA provides a list of chemicals know to cause cancer and/or reproductive harm:

Children’s Health – International pediatric consensus statement regarding children’s susceptibility to toxic chemicals: This contains a link to 120 scientific papers presented at the Conference on Children’s Susceptibility to Environmental Hazards.

Federal focus on children’s environmental health including policies designed to protect children:

It is useful to directly consult the medical literature to obtain current information. The National Library of Medicine access to peer reviewed medical studies on chemicals and mixtures including crude oil is at:

For up to date information and ways to help with the Gulf oil disaster see:


Michael R. Harbut, MD, MPH, FCCP
Professor, Internal Medicine, Wayne State University
Chief, Center for Occupational & Environmental Medicine

Director of the Environmental Cancer Initiative
Karmanos Cancer Institute
Providence Hospital
118 N. Washington, Royal Oak, Michigan 48067-1751


Kathleen Burns, Ph.D.



Lexington, Massachusetts

(781) 861-1108


[1] The exposure of susceptible individuals, such as newborns and people with specific health problems, may result in acute exposure health effects at levels that would not result in observable harm in healthy adults.

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