Risk is defined as the probability (words in bold are defined in the glossary) of injury, disease, or death under specific circumstances. All human activities carry some degree of risk.
Environmental risk is the risk associated with the likelihood or probability that a given chemical exposure or series of exposures may damage human health. Environmental risk takes two factors into account: the amount of a chemical present and its relation to the amount the exposed person can tolerate. Each person reacts to risk situations differently, both physically and mentally.
It is very difficult to come up with the precise risk associated with toxic chemicals. With certain types of chemicals, when someone is exposed to a high level, that person immediately experiences some form of injury, perhaps even death. This makes it easy for epidemiologists to determine the cause. However, there are instances of everyday environmental threats for which there are no immediate observable forms of injury or disease. For example, a person who has smoked heavily for 20 years may contract cancer only years later. It is known that the more cigarettes you smoke, the greater your chances or risk of developing lung or other forms of cancer. The risk may not be obvious to smokers because sometimes it takes years for cancer to develop.
The public seeks and deserves information on the safe levels of toxicants in foods, water, or air. The term "safe" in common usage means "without risk." However, scientifically speaking, there is no definite way to determine the conditions under which a given chemical exposure is likely to be absolutely without risk. That is where the science of risk assessment comes into play. It would be ideal if EPA could guarantee "zero risk" for a certain chemical, but that is often not possible to achieve without prohibiting all uses of the chemical. Science can, however, describe the conditions under which risks are so low that they are generally considered to be of no practical consequence. Informing the public as to which chemicals or technologies are hazardous is a realistic goal of EPA.
You will often hear the words chronic vs. acute associated with risk. An acute health risk is a risk which is currently dangerous and needs to be dealt with immediately, sometimes within hours or days. A chronic health risk may persist for a long time without showing any significant effect. Take suntanning. It poses an acute health risk when a person is out in the sun all day and develops a painful sunburn. Remedies applied in the short run may consist of a lotion or aloe to ease the pain or heal the blisters. In contrast, suntanning can pose a chronic health risk if a person sunbathes frequently over many years. Such a person may never experience acute sunburn, but may have an increased chronic risk of developing skin cancer later in life.
Dose and response are usually used together in determining risk. Dose refers to the amount of a certain chemical to which someone is exposed. Response refers to a person's reaction to that exposure.
Certain scientific terms of measurement are used to describe risk after it is assessed. Scientists may come up with a figure like 1 x 10-5(0.00001) after they assess the risk of a pesticide used on certain fruits and vegetables. It means that one person in a 100,000 people who eat the food sprayed with that pesticide may contract cancer. The use of these numbers represents a method that EPA uses to express the risk in terms of human health.
Another common term the Government uses is parts per million (ppm). For instance, there maybe 1 ppm of a chemical in a pesticide that is sprayed on crops. To put this unit of measurement in perspective one part per million is equivalent to one facial tissue in a stack taller than the Empire State Building.
FIFRA offers EPA many risk management options to reduce risks wherever possible--without doing away with the benefits of a pesticide. For example, depending on the nature of EPA concerns, such options might include: requiring protective clothing or equipment to minimize risks to pesticide applicators, reducing the rate or frequency of application to lower pesticide residue levels on harvested crops, or imposing national or regional restrictions against using a pesticide in areas where it could contaminate ground water.
FIFRA also gives EPA the authority to cancel a pesticide or issue an emergency suspension. Strong evidence is needed for such an action and it clearly represents a challenging risk management situation. Making decisions on the regulation of pesticides is just one example of the risk management process at EPA. However, before any decisions made, EPA needs to assess the risk involved. The next section describes the risk assessment process.
There are four parts to every risk assessment:
In the example using drinking water, the population that drinks the water would be evaluated, so that scientists could have a clear picture of who was actually exposed to the chemicals in the water. How much water do people drink each day? Knowing such information makes it easier to assess the risks. Sometimes, when no exposure data are available, scientists must use assumptions to make estimates.
The key to communicating any risk situation successfully is realizing that each person reacts to the situation differently. In fact, different publics even define the word "risk" differently. In a community, "publics" include parents, children, politicians, economic experts, scientists, and even employees who work at a plant that maybe causing environmental problems in the community.
An employee may look at the risk of being unemployed as greater than the risk of chemical exposure. A parent may view any risk to children, no matter how small, with outrage. EPA tries to take into account these different risk perceptions. To the Government scientist, risk means hazards presented by a chemical or a situation. Some social scientists have defined risk perception as hazard plus outrage.
Scholars who study the way people understand risk have focused on how the public reacts to risk situations. They can then guide experts and Government decision-makers in the process of making risk management and communication decisions.
Studies have shown that a risk is much more acceptable to people than an involuntary risk. People are willing to engage in voluntary risks. People feel safer when they are in control of a situation.
Most people view driving a car as a safer activity than being a passenger in a plane, even though the risk of dying in a car crash is 1 in 100 in a lifetime.... and less than 1 in a 1,000,000 in an airplane.
Since cancer is of great concern to people, shown below are various cancer risks from environmental agents:
| Cancer-Causing Agents or Situations | Approximate Lifetime Risk of Cancer | |
|---|---|---|
| 1. | Exposure to the Sun (skin cancer) | 1 in 3 |
| 2. | Cigarette smoking (based on smoking a pack or more per day) | 8 in 100 |
| 3. | Natural radon in indoor air at home | 1 in 100 |
| 4. | Outside radiation (radon and cosmic rays) | 1 in 1,000 |
| 5. | Persons in room with a smoker | 7 in 1,0000 |
| 6. | Human-made chemicals in indoor air at home | 2 in 10,000 |
| 7. | Outdoor air in industrialized areas | 1 in 10,000 |
| 8. | Human-made chemicals in drinking water* | 1 in 100,000 |
| 9. | Human-made chemicals in most foods | 1 in 100,000 or less |
| (a) 2 oz. of peanut butter per week (naturally occurring aflatoxin present) | 8 in 100,000 | |
| (b) one meal per year of small Lake Michigan trout | 1 in 100,000 | |
| 10. | Chemical exposure at most uncontrolled hazardous-waste sites | 1 in 10,000 to 1 in 1,000,000 |
| *Some chlorinated waters may have slightly higher risks. Chlorination is used to destroy disease-causing organisms often found in drinking water. | ||
Smoking cigarettes over a lifetime yields a voluntary risk of 8 in 100 of contracting cancer. The most common form of cancer from cigarettes, lung cancer, is not readily curable. It is important to note that nonsmokers, in the presence of smokers, also experience a very high risk of cancer--7 in 1,000, or only about 10 times less than the smoker. Quitting smoking not only reduces the risks to smokers, but also to those around them.
An extremely high risk of cancer (an average of 1 in 100) results from naturally occurring radiation, in the form of radon in the home. It is estimated that 4,000-5000 deaths per year occur in the Great Lakes Region (Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin) due to radon exposure in homes. EPA has frequently recommended that people test their homes for radon, but less than 5 percent have done so nationally. Yet exposure to radon, like smoking cigarettes, is known to cause lung cancer.
Studies show that people are less concerned about natural risks, such as radon, than they are about unfamiliar risks, such as living near an uncontrolled hazardous waste site. Most hazardous waste sites before cleanup pose cancer risks ranging from one in a million to one in ten thousand--or 100 to 10,000 times less than posed by radon in homes. But people are far more concerned about getting cancer from hazardous waste sites, even if cancer risks are as small as one in a million. The hazardous waste site is human-made, less understood, and is therefore perceived to be more threatening than radon in homes. However, radon in homes presents far greater danger than most hazardous waste sites. Fortunately, simple measures exist to reduce radon. EPA encourages homeowners to test their homes and, if necessary, take steps to reduce radon. (For more information write to: Radon Publication Coordinator, EPA Region 5, 77 West Jackson Blvd., Chicago, IL 60604.)
Researchers have shown that the indoor air in homes has chemicals other than radon with the potential to cause cancer. Some of these human-made chemicals found include solvents in paints, cleaning agents, and pesticides. EPA has found that indoor air cancer risks from these chemicals (2 in 10,000) generally are greater than risks from cancer-causing agents found outdoors in heavily industrialized areas (1 in 10,000). This was an unexpected finding.
You can reduce your exposure to cancer-causing agents in the home by minimizing your use of solvents, cleaning products, or deodorizers containing chloroform, trichloroethylene, tetrachloroethylene, benzene, and dichlorobenzene.
If you are using chemicals to strip wood, you should use protective gloves, good ventilation or a carbon respirator to protect yourself from these chemicals. If you use pesticides in and around your home, or have them applied professionally, ask if they cause cancer or have other serious toxic effects. As a general rule, pesticides should be used only if absolutely needed.
Homes may also contain formaldehyde as a component of glue in wood paneling or in insulation (urea-formaldehyde foam). Find out if wood paneling contains formaldehyde, particularly if you plan to use a great deal of paneling in your home. Also, before you buy or sell a home, find out if urea-formaldehyde insulation foam is present. If so, you may wish to test the air for formaldehyde.
Asbestos is also a known human lung carcinogen and you should know if your home contains asbestos. Asbestos in homes is most often found in insulation for hot water pipes or furnaces. Asbestos poses a danger when the fibers are loose or crumbling. To determine if material contains asbestos, send a bulk sample to a laboratory. But be careful not to disturb the suspected material when collecting a sample. Do not try to remove asbestos yourself; there are licensed asbestos contractors for that. A list of approved laboratories and contractors is available from your EPA office at the address for radon publications on page 11. Cancer risks from human-made chemicals in drinking water and in foods are generally low. You can reduce both human-made and natural cancer-causing chemicals in your diet by eating foods low in fat. A diet high in fiber reduces the chances of colon cancer, a leading form of cancer. Washing or peeling fruits and vegetables will help remove traces of pesticides.
There are also significant non-cancer environmental risks that we often do not think about. The risk of death from a fall in your lifetime is 4 in 1,000; from drowning, 3 in 1,000; from fire, 2 in 1,000; and, electrocution 4 in 10,000. Numerous safety measures exist which, if used, will reduce these other risks, too.
Pesticides and other chemicals were also found to have undesirable risks to wildlife. In addition, very significant potential risks to animal and plant life, including agriculture, may result from global warming, stratospheric ozone depletion, and accidents involving chemical or nuclear materials. To prevent present and future damage to ecosystems to which we are directly dependent, EPA believes additional environmental protection measures are needed. Similar conclusions regarding the need to protect ecosystems were reached in September 1990, by the Science Advisory Board, an independent advisory group to EPA.
"A Risk Analysis of Twenty-six Environmental Problems," U.S. EPA Region 5, 1991.
Reducing Risk: "Setting Priorities and Strategies for Environmental Protection," U.S. EPA, Science Advisory Board, Washington, DC, September 1990.
77 West Jackson Blvd. Chicago, IL 60604 (312) 353-2072
In Illinois 1-800-572-2515
In Indiana, Minnesota, Michigan, Ohio, Wisconsin 1-800-621-8431
Covello, Vincent T., Peter M. Sandman, and Paul Slovic, "Risk Communication, Risk Statistics and Risk Comparisons: A Manual for Plant Managers." Chemical Manufacturers Association Workshop, 1988.
Covello, Vincent T., Detlof von Winterfeldt and Paul Slovic, "Communicating Scientific Information About Health and Environmental Risks: Problems and Opportunities from a Social and Behavioral Perspective." Risk Communication, The Conservation Foundation: Washington, DC, January 1986.
Crouch, E.A.C. and R. Wilson, 1984. "Inter-Risk Comparisons." Assessment and Management of Chemical Risks, ed. J. Rodricks and R. Tardiff, Washington, DC: American Chemical Society, pp. 97-112.
Ruckelshaus, William D., "Risk, Science and Democracy: Part 1." Chemtech, November 1987, pp. 658-662.
Ruckelshaus, William D., "Risk, Science and Democracy: Part 2." Chemtech, December 1987, pp. 738-741.
Sandman, Peter M., "Explaining Environmental Risk." TSCA Assistance Office, U.S. Environmental Protection Agency, November 1986.
U.S. Department of Health and Human Services. U.S. Environmental Protection Agency, A Citizen's Guide to Radon: What It Is and What To Do About It, Washington, DC, August, 1986.
U.S. Environmental Protection Agency, "A Risk Analysis of Twenty-six Environmental Problems," U.S. EPA Region 5, Chicago, Illinois, 1990.
U.S. Environmental Protection Agency, "Environmental Risk." EPA Journal, Office of Public Affairs, U.S. EPA, Washington, DC, Volume 13, Number 9, November 1987.
U.S. Environmental Protection Agency, "Guidelines for Risk Assessment." Federal Register, Washington, DC, 51(185): 33991-34053.
U.S. Environmental Protection Agency, Lawn Care For Your Home, Office of Public Affairs, U.S. EPA Region 5, Chicago, Illinois, February, 1988.
U.S. Environmental Protection Agency, Science Advisory Board, Reducing Risk: Setting Priorities and Strategies for Environmental Protection, Washington, DC, September, 1990.
U.S. Environmental Protection Agency, Seven Cardinal Rules of Risk Communication, Washington. DC, April, 1988.
U.S. Environmental Protection Agency, Wood Preservatives for Consumers, Office of Public Affairs, U.S. EPA Region 5, Chicago, IL, 1987.
Page maintained by: Jeff Kelley, Office of Public Affairs ([email protected])
Last Updated: May 19, 1997
URL: http://www.epa.gov/Region5/risk.htm