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Toxicology is a difficult scientific field that attempts to determine whether chemicals are harmful. There are many different ways that a chemical can cause harm, all influenced by the dosage and the route of exposure. This chapter gives a basic explanation for the public of how the toxicity, and therefore safety, of active ingredients is determined. Government regulation of repellent products provides considerable safety because groups of toxicologists give careful consideration to the amount of exposure and the potential for harm. Labels on products that limit the number of applications or restrict who can use a product are based on careful science.

The organisms that make Natural Products have been producing tens of thousands of different chemicals, totalling billions of tonnes every year, for billions of years. Hence, organisms have evolved to survive, indeed thrive, in the presence of these chemicals. The mechanisms evolved by organisms to cope with their chemical load are likely to be the same mechanisms used by organisms, including humans, to cope with new chemicals introduced into use by humans. This chapter shows how the subjects of toxicology and ecotoxicology can usefully be informed by the knowledge of NPs.

This chapter provides an overview of the book and a summary of each subsequent chapter. It highlights the volume's two major goals: to examine the range of methodological decisions and interpretive judgments that permeate policy‐relevant scientific research and to explore ways of making these choices more responsive to a range of public values (in addition to those of deep pockets, which have abundant resources to spend on research). It also introduces readers to the book's central case study, hormesis, which involves seemingly beneficial effects produced by low doses of substances that are normally toxic. Chapters 2 and 3 perform two preliminary tasks: (1) They clarify the major categories of value judgments that contribute to differing evaluations of the generalizability and regulatory implications of hormesis; and (2) they argue that societal values should not be completely excluded from influencing any of these categories of judgments. Chapters 4 through 6 develop the book's three primary lessons, corresponding to the three “bodies” that Sheila Jasanoff emphasizes as central to obtaining trustworthy public‐policy guidance from scientific experts. These lessons concern how to safeguard the body of scientific knowledge from interest groups, how to ascertain the best advisory bodies for guiding policy makers and directing the course of future research, and how to provide the bodies of experts themselves with an ethics of expertise. Chapter 7 argues that the lessons drawn in chapters 2 through 6 are applicable not only to the hormesis case but also to other areas of policy‐relevant research, such as endocrine disruption and multiple chemical sensitivity (MCS).

This chapter examines the history of hormesis research as an important case study of the ways in which methodological and interpretive judgments enter scientific practice. It organizes these choices into four major categories. First, judgments pervade the choice of research projects and the design of studies. One of the important questions in this regard is what kinds of studies to prioritize, given the limited funding available to examine the low‐dose effects of toxicants. Second, crucial decisions are involved in developing scientific language. The hormesis case study (as well as the multiple chemical sensitivity and endocrine disruption cases examined in Chapter 7) provides vivid examples of how the choice of scientific terms and categories can subtly influence policy discussions. Third, judgments play a crucial role in the interpretation and evaluation of studies. This third category of methodological choices is especially important to understand in the hormesis case, because it is largely responsible for the disagreements between proponents and opponents of claims about the generalizability and regulatory implications of hormesis. Fourth, there are important decisions to make about how to apply research results in the context of formulating public policy. For example, efforts to apply hormesis to regulatory policy must come to grips with difficult questions about how to balance potentially beneficial and harmful effects of toxic chemicals.

This final chapter reviews the book's major claims and considers important directions for future scholarship. The analyses in the preceding chapters suggest at least three promising avenues for future work: (1) further philosophical studies of the roles that various sorts of values should play in scientific research; (2) new scientific investigations of the biological effects of toxicants at low doses; and (3) ongoing social‐scientific research on how to incorporate a representative range of societal values in science. Regarding the role of values in science, leading philosophers of science disagree both about the extent to which scientific theory choice is underdetermined by epistemic values and about the conditions under which nonepistemic values should be employed in resolving this underdetermination. Related questions include whether the conceptual distinction between epistemic and nonepistemic values holds up to critical scrutiny and whether it is possible to draw a convincing distinction between practical decisions about how to act and epistemic judgments about what to believe. Regarding new scientific investigations, it is probably more important in the near future for scientific research to focus on hazards like endocrine disruption and toxic‐chemical mixtures than on hormesis, especially because sensitive populations like children are probably already exposed to mixtures of toxicants at levels above the hormetic dose range. Nevertheless, hormesis research may still be valuable in some fields, such as pharmaceutical development. Finally, with respect to social‐science research, it would be helpful to develop new strategies for addressing conflicts of interest, new research on the sorts of deliberative mechanisms that are effective in particular contexts, and further studies on how to effectively disseminate scientific information to its recipients.

Chapter 1 provides a map of key environmental health research and regulatory institutions, including the National Institute of Environmental Health Sciences (NIEHS), the National Toxicology Program (NTP), and the Environmental Protection Agency (EPA). It also considers the goals and perspectives of the chemical industry and of environmental health and justice activists.Focusing, then, on the contentious politics of the environmental health arena, it explores how the practices of environmental health scientists have been shaped by the forces and struggles in the field in which they operate

Chemical safety is the general term for managing the hazards and risk associated with particular chemicals, both to protect workers and residents in the community. Hazards associated with chemicals may include poisoning, irritation, chemical burns, foul odour, allergies, explosion, fire and combustion products, release of heat or induction of cold. A particular problem with chemical safety occurs when workers enter confined spaces, places that are enclosed such air does not circulate freely and gases or vapours can collect at high concentrations and cause poisoning. Toxicology is the science that studies how chemicals are handled in the body and how they affect the body in causing injury or illness.

Several types of chemical information are needed including information on inherent chemical characteristics, chemical production and use, chemical release and exposure, and alternatives to hazardous chemicals. The Environmental Protection Agency and other government agencies and private services have developed many tools, models and estimation techniques for generating the needed data. New advances in computational toxicology can now provide “automated high-throughput” estimates of various chemical characteristics without the slow and costly chemical testing of the past. There are also significant efforts to improve chemical information transfer within supply chains and increase chemical information disclosure to the public.

This chapter examines the role of the University of Chicago Toxicity Laboratory in the development of toxicology and in scientific efforts to support defence during World War II. The Toxicity Laboratory was one of the first institutions devoted entirely to toxicological research. Some research topics pursued there provide important links in such areas as the joint toxicity and resistance to antimalarial drugs. E. M. K. Geiling directed several programs on behalf of the war through the Toxicity Laboratory. In addition to studying antimalarial drug therapies, scientists at the Toxicity Laboratory devoted considerable effort to the analysis of nitrogen mustards. In general, Geiling and the growing group of scientists at the Tox Lab carried out a broad range of studies with implications for pharmacology and for toxicology as a distinct discipline.

This chapter highlights lessons learned from a hundred years of risk assessment from pesticides. As the scale of agriculture developed to industrial proportions, farmers increasingly relied on chemical inputs, specifically insecticides, to control crop damage as a result of insect infestations. The methods developed by E. M. K. Geiling and FDA scientists revealed the value of toxicology in characterizing risks of chemicals in the marketplace. Meanwhile, the book Silent Spring highlighted the tragic irony of legislation and pesticide use. While organophosphates posed a significant risk to humans and wildlife, most remained in the market until the EPA completed its comprehensive review in 2006. To this day, organophosphates are still among the most widely used pesticides in the world, with tragic consequences for farm workers, children, and wildlife populations.

Chapter 2 examines how scientists have used the ongoing conflicts, challenges, values, and narratives embedded in the contentious politics of environmental health to articulate the persistent challenges facing their field. It defines the concept of a “consensus critique”—an effort to bring stakeholders together around a set of shared concerns that transcend their substantive political, economic, and/or social differences. In this case, the consensus critique points to technical challenges and procedural limitations extant in toxicology testing, the environmental health risk assessment and regulation that diverse stakeholders tend to agree are problematic, even as they disagree vehemently about substantive and political matters, such as specific regulations.

This chapter describes the basic principles of toxicology and their application to occupational and environmental health. Topics covered include pathways that toxic substances may take from sources in the environment to molecular targets in the cells of the body where toxic effects occur. These pathways include routes of exposure, absorption into the body, distribution to organs and tissues, metabolism, storage, and excretion. The various types of toxicological endpoints are discussed, along with the concepts of dose-response relationships, threshold doses, and the basis of interindividual differences and interspecies differences in response to exposure to toxic substances. The diversity of cellular and molecular mechanisms of toxicity, including enzyme induction and inhibition, oxidative stress, mutagenesis, carcinogenesis, and teratogenesis, are discussed and the chapter concludes with examples of practical applications in clinical evaluation and in toxicity testing.

From the early 1950s through early 1960s, Dow and Shell marketed DBCP before toxicological testing was complete. Marketing techniques used the language of science to teach farmers about DBCP’s then-unfamiliar target pests—near-microscopic, wormlike nematodes—and said DBCP-based products would boost profits by controlling them. Confidence in new pesticides was not unbounded, as many worried about the harm to human health. Toxicology and government regulation seemed to resolve the tension between pesticides’ benefits and risks. In the case of DBCP, however, animal testing had alarming results, notably, reproductive problems in males. Companies and regulators together downplayed these results in favor of an interpretation of DBCP as “safe for human use.” Production and use of DCBP continued with few protections for those exposed.

This chapter details how Uruguayan experts and citizens negotiated, translated, and “localized” global biomedical expertise, as well as how social theories of risk, vulnerability, and human nature became embedded in public-health interventions and scientific research. The chapter examines the biopolitical nature of the state’s Official Protocol and how it was both effectively deployed and continuously resisted, sometimes through double meanings associated with the oft-repeated phrase, “we are all contaminated.” The chapter chronicles the ways dissident scientists created new biomedical “artifacts” by generating and expanding toxicological data and pediatric case files, lending evidentiary support to social-movement characterizations of the weight of suffering and the geographic distribution of risk. The chapter argues that a central dimension of this scientific research and practice was its symbiosis with the social movement and the social proximity of clinicians to the lived experience of patients and families.