Quantitative risk assessment is now widely used throughout government and industry to "prove" that a proposed chemical exposure will produce only "acceptable" damage to humans. For example, a quantitative risk assessment for a proposed incinerator will "prove" that "only" one person out of a million exposed people will be killed each year by air pollution from the incinerator. No scientists actually believe that humans have sufficient knowledge to measure risks from toxic chemicals accurately or precisely or completely. For example, the U.S. Environmental Protection Agency's Science Advisory Board recently said that risk analyses "always will be imperfect tools" and "No matter how much the data and risk assessment techniques are improved... EPA's judgments [based on risk assessment] will entail a large measure of subjective judgment."[1]

This inherent uncertainty in risk assessment means that clever people can manipulate data, and can manipulate unspoken assumptions, to achieve any quantitative result they choose. In fact, it is common for risk assessors to select the goal that their risk assessment is supposed to achieve (onein-a-million is a common goal), then to manipulate the data and assumptions to come up with the "right" answer. The result is usually expressed as a single number and such numbers look very precise and scientific even though they may be based only on estimates or guesses, or may even have been fabricated.

For the past six years, Mary O'Brien has edited the JOURNAL OF PESTICIDE REFORM and has served as staff scientist of the Northwest Coalition for Alternatives to Pesticides in Portland, Oregon. For six years she has seen risk assessments used by scientists employed by polluters to justify exposing people to toxic chemicals.

"Worker inhalation and absorption of workplace toxics is approved via risk assessment," she says. "The spraying of pesticides on schoolgrounds, roadsides, over urban areas and forests, and on the nation's food supply is dubbed acceptable via risk assessment. The degradation of our drinking water supplies, aquifers, and air is approved via risk assessment."

Ms. O'Brien believes that risk assessment should be put on the back burner and, in its place, we should substitute a formal search for alternatives. Instead of asking "How much human health damage is acceptable?" we should start asking "How quickly can we install or use practices that will result in the least use of, and exposure to, toxic chemicals?"

The basic goal of a risk assessment is to evaluate the potential consequences of a decision, recognizing that much necessary information is not available and may never become available. Numerous wise approaches are available to replace risk assessment, and they must often be used in combination with each other:

1. Qualitative risk assessments. These methods involve looking at worst-case environmental and social consequences of inadequate information, missing information, non-scientific information (complaints by workers about their experiences on the job, for example), epidemiological information, and suspicions about cumulative effects. A "chemical profile" that looks at all aspects of a chemical (known and unknown) can be extremely revealing. (See RHWN #169.) Instead of spending vast sums on risk assessment for particular chemicals, perhaps a review of available information is sufficient to say, "This chemical seems to cause problems among laboratory animals and workers. We don't know very much about its mechanisms of toxicity, we'll never know what it does to people in combination with the hundreds of other chemicals they're exposed to, so we'll never be able to produce a convincing risk assessment. Therefore instead of producing a scientific sham risk assessment let's seek alternative ways of getting the job done (whatever the job is), reducing or even eliminating use of this potentially harmful chemical."

2. Labeling products and processes with all toxic chemicals used. If all workplace processes are labeled (every pipe, every vat, every drum, as is required by the New Jersey Worker and Community Right to Know Law), and all consumer products are labeled with their toxic ingredients, citizens can at least make informed choices about what they want to expose themselves to. Prop 65 in California requires that any person who knowingly and intentionally exposes another person to a carcinogen, or to a chemical known to cause reproductive hazards, must give clear and reasonable warning to the person exposed. Let the consumer be informed.

3. Some chemicals can be phased out by regulating particular compounds or particular processes. DDT has been banned for sale in the U.S.; Sweden has given its pulp and paper mills a deadline for near-zero discharge of chemical compounds containing chlorine; if the "Big Green" initiative passes in California this November, use of carcinogenic pesticides on California food will end within 5 years. Just say "no" to some chemicals.

4. Require honesty about ignorance in quantitative risk assessments. Where quantitative risk assessments are used, they could be supplemented by formal statements about their shortcomings. Such statements could include standards that have been set elsewhere to control this chemical; the kinds of scientific tests that have not been done on a chemical (for example, studies of chronic nerve damage); whether infants, old people, and chemically sensitive people were considered in the assessment; whether degradation byproducts of the chemical were considered in the assessment (for example, DDT breaks down in the environment to a chemical called DDE, which is more toxic than DDT); what is not known about chemicals in combination with each other. People need to know that, with toxic chemicals, the unknowns are much larger than the knowns.

5. Require an official search for alternatives to toxics. Often, a formal search for alternatives to toxics will make a risk assessment unnecessary. "Anyone who sees chlorine-free paper products (e.g., magazines, copy paper, toilet paper, tampons) available in Sweden and Austria realizes the absurdity of estimating how many dioxin-laden fish caught below a chlorine-using pulp mill constitute 'acceptable risk'," says Mary O'Brien.

"The first step of admitting that it would be desirable to reduce use of pesticides and other toxics is generally the hardest for most agencies or industries," she says. But getting agencies and industries to state such a preference is crucial. Once we reach agreement that toxics use reduction is desirable, then the formal search for alternatives can be initiated and we can stop relying on the narrow, deceptive "science" of quantitative risk assessment.
--Peter Montague, Ph.D. =============== [1] REDUCING RISK: SETTING PRIORITIES AND STRATEGIES FOR ENVIRONMENTAL PROTECTION (Washington, DC: Science Advisory Board [A-101], U.S. Environmental Protection Agency [401 M St., Nw, Washington, DC 20460], September, 1990, pg. 16. This 26-page summary report is available upon written request from the Science Advisory Board at the address given (don't forget the A-101); and be sure to ask for the three separate Appendices as well. To understand the federal government's viewpoint toward risk assessment, you might want to get the Council on Environmental Quality's book RISK ANALYSIS: GUIDE TO PRINCIPLES AND METHODS FOR ANALYZING HEALTH AND ENVIRONMENTAL RISKS. Available for $17.50, plus $3.00 shipping, from National Technical Information Service (ntis): phone (703) 487-4650. Ask for document Pb 89-137772. [We have taken material from two articles by Mary O'brien writing in the JOURNAL OF PESTICIDE REFORM (JPR), Vol. 8 No. 1, pgs. 7-13 and Vol. 10, No. 1, pgs. 2-6. We urge readers to subscribe to JPR: individuals, $15/yr; institutions, $25/yr from: Northwest Coalition for Alternatives to Pesticides, P.O. Box 1393, Eugene, Or 97440. Back issues are available for $3 each, or $10 for a year's worth.."

Descriptor terms: risk assessment; journal of pesticide reform; mary obrien; workers; occupational safety and health; labelling; chlorination; chlorine;