Environmental Risk Analysis: A Review of Public Policy Issues VI

98-618 ENR

CONTENTS FOR THIS SECTION

The Information Value of Risk Analysis

Key Factors Determining the Quality of Information Provided
Quality of the Database

The Information Value of Risk Analysis

There appears to be general agreement that policymakers need more information to inform risk management decisions. Views diverge, however, regarding the type of information needed and whether it is best provided by risk analysis. The debate might benefit, therefore, from explicit consideration of what information risk analysis provides.

Key Factors Determining the Quality of Information Provided. Under ideal conditions, a risk analysis might gather, organize, and summarize all of the important information relevant to hazard management. It would include qualitative as well as quantitative information about the characteristics of the hazard, exposed population, potential effects, and potential effects of available management strategies; describe scientific uncertainties; and provide a range of forecasts based on alternative, scientifically plausible assumptions about the relationship between exposure to the hazard and potential health or environmental effects.

In practice, however, the type of information provided by environmental risk analysis varies from abundant (but often with critical gaps) to superficial, from accurate to biased, because risk analysis is a field of inquiry rather than a single method. Risk analysts study hazards using a variety of procedures adapted from other fields of study. Sanitary and industrial engineering, psychology, economics, sociology, statistics, and operations research, for example, have provided models and procedures used by risk analysts. Because some of these methods were developed for different purposes (for example, to determine actuarially sound life insurance rates), they often have not been scientifically validated for, and are difficult to apply to, environmental hazards. The defining characteristic of most methods used in risk analysis is a reliance on past experience (with the hazard or with an analogous hazard) to predict future events. The less directly relevant and extensive the past experience, the poorer the quality of data and the subsequent analysis.

A second consideration is that risk analysis is a tool for evaluating what is known about things that cannot be known with certainty - that is, it is only used to describe the effects of hazards that are unpredictable due either to their randomness or to lack of data or scientific understanding of the principles that govern their occurrence. Its methods were developed to allow agencies to implement legislation despite incomplete data and scientific understanding.

Risk analysis always produces an estimate, never an exact prediction, and estimates vary in quality. (Weather forecasts, for example, are relatively well informed risk estimates.) Thus, risk analysts can only discuss the likelihood of various outcomes and, at best, may present risks as statistical probabilities. If there is no past experience with a hazard, there is no basis for any forecast, much less a quantitative estimate (although risk estimates may be made based on conceptual models or experiences with similar hazards.) If there is experience but no record to ensure accurate recall, risk estimates are likely to be unreliable.

Finally, there are times when risk analysis can provide no information at all, because some environmental hazards and effects defy risk analysis, even when data are abundant-e.g., as with long-term weather predictions. Science cannot always explain complex or unusual relationships between the exposures to hazards and the potential health and ecological effects. For example, chemicals in the environment that suppress immune systems may not be recognized as hazards, because their effects will be seen as a variety of health problems, each of which may be attributed to a different cause. In other cases, only people with certain innate characteristics may be affected by exposure to a toxic substance.

Quality of the Database. The quality of available data largely determines the quality of information that can be provided by a risk analysis. Thus, the NAS concluded in 1983 that the most effective way to improve risk assessment in the federal government is to improve the quality and comprehensiveness of knowledge.53 The data situation 10 years later was summarized in a report by the Congressional Office of Technology Assessment (OTA).54 It estimated that 62,512 chemicals were in commerce in the United States, and another 1500 new chemicals entered the market annually. 55 Environmental experts believed that "good" data on health effects existed for only 10% of commercial chemicals, according to OTA. In a 1995 report, OTA estimated that roughly 30,000 of the chemicals that have been in U.S. commerce since 1976 are polymers that present little health risk. 56 Another 25,000 are produced in low volume (less that 10,000 pounds per year, including some chemicals which no longer are in production.) There remain approximately 15,000 chemicals produced in significant volumes. About 3 or 4 thousand chemicals are produced in amounts greater than one million pounds per year. OTA reported, "For perhaps thousands of these chemicals of potential concern, toxicity and exposure data remain inadequate for risk assessment."57 Of course, many may be harmless, but according to NAS, data are also inadequate for many chemicals that Congress has deemed "hazardous." NAS evaluated the availability of data for risk analyses for 189 hazardous air pollutants and concluded EPA did not have "sufficient data to assess fully the health risks... within the time permitted by the Clean Air Act Amendments of 1990." 58 In 1993, OTA reported that at least 12 federal agencies were conducting health risk assessment research to fill the gaps in scientific understanding, but their efforts were poorly coordinated and supported at a level that is less than 0.5% of the cost of complying with EPA regulations. (This figure does not include research relevant to the analysis of ecological risks.)

The Environmental Defense Fund (EDF) reported in 1997 on research conducted to determine the adequacy of test data for chemicals produced in amounts greater than one million pounds per year that have been identified as subjects of regulatory attention.59 The adequacy of test data was determined based on the public availability of the "minimum screening information data set" that was created by the Organization for Economic Cooperation and Development (OECD) Chemicals Program in 1990. This data set is adequate to perform preliminary assessment of the potential human health hazard of a chemical, but does not provide sufficient data to conduct a comprehensive health risk assessment, according to EDF.60 EDF drew a random sample of 100 chemicals and found that 71% did not meet the OECD minimum data requirement.61 Most of the chemicals in the sample had been tested for their ability to cause mutations (genetic toxicity) and developmental toxicity, but there were no reproductive toxicity data for 53% of the chemicals.62 Most of the chemicals had not been tested for any form of toxicity due to chronic exposure. According to the authors of the study, the Chemical Manufacturers' Association (CMA) independently concluded that only 53% of the chemicals lacked adequate public data, but acknowledged that a key international chemical database had very recently become available for public scrutiny.63 Critics of the EDF study, however, countered that up to three-fourths of chemicals have been adequately evaluated.64

EPA evaluated the availability of toxicity data for industrial chemicals produced in high volumes and recently reported that there was a complete set of health and environmental effects data for only 7%.65 There were no publicly available data for 1,216 of the 2,863 chemicals evaluated by EPA. EPA and Vice President Gore have called on the chemical industry to produce data to fill the gaps at an EPA-estimated total cost of $427 million.66 That cost represents about 0.2% of total annual sales of the top 100 U.S. chemical companies, according to EPA.67 The chemical industry supports the initiative provided it remains voluntary, but estimates that the cost could approach $765 million and place U.S. companies at a competitive disadvantage internationally.68

ENDNOTES

53 NAS, National Research Council. Risk Assessment in the Federal Government: Managing the Process. Washington, DC, National Academy Press, 1983. p.5-6.

54 U.S. Congress, Office of Technology Assessment. Researching Health Risks, OTA-BBS 570. Washington, U.S. Govt. Print. Off, Nov.1993. 228 p.

55 0TA used the phrase "chemical in commerce" to mean all chemical substances that are potentially regulated under the Toxic Substances Control Act which covers most chemicals except drugs, pesticides, tobacco, food products, food additives, and radioactive materials.

56 U.S. Congress, Office of Technology Assessment Screening and Testing Chemicals in Commerce, OTA-BP-FNV-166. Sept.1995. Washington, DC, U.S. Govt. Print. Off 126 p.

57 Ibid. p.11.

58 NAS, National Research Council. Science and Judgment in Risk Assessment. p. 8-13.

59 Environmental Defense Fund. Toxic Ignorance: The Continuing Absence of Basic Health Testing for Top-Selling Chemicals in the United States. New York, NY, The Environmental Defense Fund, Inc 1997. 65 p.

60 According to EDF(P.13), the test data include data on acute toxicity, repeated dose toxicity, genetic toxicity (in vitro and in vivo), reproductive toxicity, and developmental toxicity.

61 Ibid. p.15.

62 Ibid.

63 Roe, David, Bill Pease, Karen Florini, and Ellen Silbergeld. "Understandable Skepticism, But Unavoidable Facts," Risk Policy Report, v.4, n. 10, Oct. 17, 1997. p.34.

64 Spitzer, Hugh L. and James D. Wilson. "Toxic Ignorance or Toxic Terror," Risk Policy Report, v.4, n. 10, Oct. 17, 1997. p.32.

65 EPA. Chemical Hazard Data Availability Study. April 1998.35 p. http://www.epa.gov/opptintrichemtest/hazchem.htm

66 "Testing: Few High Production Chemicals Have Basic Test Data Available, EPA Report Says," Daily Environment Report, n. 84, May 1, 1998, p. A-9.

67 Ibid.

68 "Testing: EPA Brakes Fast-Track Implementation of Test Goals for High Production Chemicals," Daily Environment Report, n. 113, June 12, 1998. p. A-8.