This book, dedicated “to all who have mixed their hands with the soil,” is the latest publication in the University of California Press series Critical Environments, which explores “the political forms of life and ecologies that emerge from histories of capitalism, militarism, racism, colonialism, and more.” Romero explains that he had originally wanted to study toxicology as an environmental scientist, to help regulate agricultural pollutants for farm workers. “I tell you this because I want you to know that when I picked up the first volume of the Journal of Economic Entomology,” the flagship journal on pest control, “I did so not just as a geographer or a historian in need of a new project, but as someone who has always been keen to figure out why agriculture in the United States is so dependent on poisonous chemicals” (2). Romero leafed through the entire set of the Journal of Economic Entomology and realized what ultimately became the thesis of his book. His argument, succinctly captured in each chapter, is “that the transition to chemical agriculture was as much a story about trying to get rid of industrial waste as it was about using chemicals to mass produce food” (3). So, rather than frame industrial waste as an economic externality, this history of capitalism illustrates how industrial by-products led to entirely new agricultural applications. (A close comparison, of course, is the meatpacking industry.) Romero argues that economic poisons displaced the problems of industrial waste by broadcasting them on the farm.The book opens with a retrospective letter to Rachel Carson. The epistolary preface recaps the environmental movement that she helped initiate. He praises her message, yet informs Ms. Carson that her critique could have gone further. She was not opposed to the discriminate use of pesticides, but Romero is. The author touches on the deaths caused by industrial poisons and expresses distrust for the stories and policies that justify their continued promotion. Romero sees the chemicalization of American agriculture as being quite different from the need to produce food. This basic message resonates throughout the book. As his letter asserts: “We have the right to know that despite some laboratory testing, we are the real guinea pigs” when it comes to ubiquitous pesticide use and residues (xiii).Chapter 1 follows arsenic waste from the copper smelters in the United Kingdom to developments in the American West. The chapter begins by stating that, as a toxic chemical for pest control, arsenic usage peaked in the mid-1940s. The chapter then goes back in time to explain the engineering of copper smelting in Cornish mines in the eighteenth century and the nineteenth-century development of white arsenic, being separated from copper in the manufacturing process. The deadly powder became popular in American agriculture in the 1860s as the copper-arsenic-based compound Paris Green, principally used to combat the potato beetle. Romero transitions to the copper deposits in Michigan and then Montana, as the American West became the “world's largest producer of arsenic waste” (29). Again, Romero shows how the arsenic supply resulted from the copper production process and not from demand for more arsenic. Legal edicts in the United States forced companies to install scrub stacks to recover arsenic from the flues of copper-roasting ovens. What to do with the growing piles of toxic pollution? Spread it on the crops! By the 1920s, arsenic dusts laced the apple groves of the western United States as a cheap pesticide for codling moths. The chapter diverges into the development of an insoluble version of the poisonous spray and concludes with the fall of the US copper industry after World War II. All in all, the chapter offers a wide-ranging education on mining and engineering, topics often neglected by agricultural historians drawn more to crops than to industrial chemistry.In chapter 2, Romero turns to cyanide fumigation, arguing that chemical pest control is an act of war. Here he recalls the work of Edmund Russell, yet only to “push beyond the coevolution of war and agriculture” or their shared infrastructure (52). Romero uses the language of warfare literally, asking if the chemical war on pests is a just war—a line of reasoning that takes the intent of insects into account. As recurs throughout Economic Poisoning, the chapter focuses on California and the development of its commercial orange groves. Entomologists looked to address the damage caused by white scale, a widespread infestation on citrus trees by the 1880s. The US Department of Agriculture experimented with fumigation tents—an apparatus placed over the entire tree—to gas the scale and their eggs with cyanide. Romero shows how nocturnal cyanide fumigation became standard practice and the subject of an invalidated patent. Fruit from fumigated groves brought higher market prices with less post-harvest processing. Fumigation also brought more pests. “With the control of one pest,” Romero explains, “others realigned their life histories to fill the abruptly vacant niches that chemical war continuously brought to the industrial citrus ecosystem” (64). This serial substitution of pests is essentially how toxic chemicals became conventional practice in American agriculture. Romero concludes by asking why we continue to poison crops and if the response is justified even in times of war. The chapter holds up as a good stand-alone read, especially for historians versed in the citrus literature.Chapter 3 covers the development and deployment of oil-based sprays, also in California citrus groves. “Despite the proven efficacy of cyanide fumigation, some citrus growers had turned to oil because it was so incredibly cheap” in the 1910s, Romero explains (76). The chapter focuses on Hunter Volck, a graduate from the University of California, Berkeley (as is Romero), who took a job at the UC experiment station and was sent to investigate the commercial groves of Southern California. Citrus growers used oil-based sprays to control those populations of scale not killed by fumigation but also to counter the associated spread of red spider mites. Volck realized that spraying refinery wastes on citrus trees had erratic results, given the uncertain toxicology of fuel oil from which it was derived. In 1907, Volck and a partner started the company Cal-Spray to manufacture the Ortho brand of on-farm chemical treatments. The chapter highlights the growth of Cal-Spray and the use of the patent system to profit from public research money. Within a few decades, oil sprays became complementary to other pesticides, and Cal-Spray went into debt, only to be bought by Standard Oil during the Great Depression. “What these companies began to recognize was that all parts of oil could be put to use if only a use for them could be found,” Romero writes (96). Agriculture became a convenient sector in which to find uses for patented products from petrochemical waste.Chapter 4 continues a theme from the previous chapter—the private capture of public funds—through a case study of the Crop Protection Institute (CPI). Unusual for its time, the CPI aimed to coordinate private funding for pesticide research at state agricultural experiment stations. Romero insists that CPI's biggest impact was the development of R&D infrastructure that “helped make toxicity-based repair the solution to agriculture's pest problems” (99). The chapter returns to World War I and the formation of the National Research Council (NRC) as a governmental hub of scientific activity. Romero describes how the wartime spirit for scientific progress found a way to strengthen the cooperative fight on American farmlands. Lack of standardized toxicological data was a problem for the agricultural chemical industry because poisons required standardized laboratory procedures for commercialization. “By the 1920s the CPI was evolving into an organization at which individual companies could get their poisons tested without having to give up propriety rights,” a shift that Romero contrasts with NRC contract policy (111). The institutional history focuses on two early projects of the CPI: first, the development of DN-Dust, a pesticide by the Dow Chemical Company in the late 1930s, and second, the first synthetic herbicide used in the United States in the early 1940s. Consequently, the CPI seemed to have served its purpose of coordinating public-private partnerships, one that, as summarized by Romero—with echoes of Jim Hightower and Jack Kloppenburg—“allowed chemical companies to benefit from publicly subsidized research” (121).1Readers might be familiar with the content of chapter 5 because Romero published an earlier version in Agricultural History.2 Within the context of the book, the story of a toxic fumigant being injected into the topsoil of a declining California crop field is a brilliant presentation of the overall argument. The soil fumigant DD, named after two novel chlorinated chemicals from Shell's petroleum waste, killed nematodes in the soil. Romero shows how the synthetic disinfectant restored crop yields; in this case, the continuous production of a single crop without rotation would not be possible” otherwise (136). The chapter also explains how Shell mechanized the application of DD through parallel developments with ammonia fertilizer. Romero provides a succinct history of industrial nitrogen fixation and the Haber-Bosch process, a history that feeds into Shell's patented technology for delivering fertilizer via irrigation water and, subsequently, directly into the subsoil through an injection method. The chemical fumigant and anhydrous ammonia were combined into a single application in 1944, epitomizing to Romero an “underground chemical warfare that revolutionized agriculture” by extending monocultures in time (137).Romero's central thesis that agriculture became a burial site for dissipating piles of cheap poisonous by-products should have a major impact on how historians discuss the topic. If crop abundance was a problem, as it often was with American agriculture in the decades before World War II, the systematic adoption of chemicals to achieve greater yields requires an explanation other than food sufficiency. Romero offers a compelling explanation. How farmers' own accounts relate to this history of chemicalization, however, is not captured by the book's institutional emphasis. As for alternative solutions, Romero worries that “we have gotten farther and farther away from the possibility of an agricultural system not built on the assumption of widespread chemical control” (142). Although it was not inevitable during the first half of the twentieth century, he wonders if it is inevitable today. Systematic change at this point would require an end to the insecticidal war.The text itself is substantiated by a heavy dose of references. The endnotes begin on page 145, yet the final pagination is 251. This speaks to one of the strengths of the monograph. In making the argument that chemical pest control was an offshoot of industrial waste, Romero has to explain many aspects of industrial manufacturing—each time with each chemical in each chapter. He meets the challenge. Every chapter has fewer notes than the previous one. Oddly, the book lacks a list of abbreviations, which would be helpful for a book chockablock with chemical compounds and administrative bodies. The date ranges covered per chapter are also difficult to find. Economic Poisoning sometimes reads like a thematic series of historical case studies. This compositional structure could be construed as a weakness or could indicate a problem of narrative coherence, but I find that the collection-of-essays approach fits with contemporary reading habits. The book asks each chapter to stand on its own merits with original content that supports a bigger argument, which Romero altogether delivers.