Int. J. Environ. Res. Public Health 2012, 9 2004 complex inquiries into the specific factual circumstances of the decision, the placement of language in the relevant statute, and the legislative intent of Congress. Thus, the outcome of questions of statutory authority in cases of statutory vagueness or ambiguity turns on the specific factual circumstances surrounding a particular decision. Figure 1. Chevron test—Two-part framework for resolving agency interpretations of statutes. Chevron established that courts should defer to reasonable agency interpretations of the agency’s authorizing statute where the statute is vague or ambiguous [49]. The Court reasoned, “When a challenge to an agency construction of a statutory provision, fairly conceptualized, really centers on the wisdom of the agency’s policy, rather than whether it is a reasonable choice within a gap left open by Congress, the challenge must fail” ([49], p. 866). Under the first step of the Chevron inquiry (Chevron Step One), the court independently analyzes the relevant statute to determine whether its meaning is clear. In other words, the court determines whether Congress has unambiguously either banned or required what the agency proposes to do ([50], p. 1667; citing [49], p. 842). Note that a court may find an unambiguous Congressional intent outside the plain words of the relevant statute. For example, in FDA vs. Brown & Williamson Tobacco (FDA vs. Brown), the Supreme Court rejected a Food and Drug Administration (FDA) assertion that the agency had authority to regulate tobacco products under the Food, Drug, and Cosmetic Act (FDCA), reasoning that authority to regulate those products under the statute would require banning them from the market, based on FDA’s findings regarding the significant health risks posed by tobacco products ([51], pp. 160–161). The Court concluded that such a ban would contradict Congress’s clear intent as expressed in then-recent tobacco-specific legislation allowing the continuing sale of tobacco products in the United States ([51], pp. 137–139). The court gave this rationale. “[T]he words of a statute must be read in their context and with a view to their place in the overall statutory scheme. … [T]he meaning of one statute may be affected by other Acts, particularly where Congress has spoken subsequently and more specifically to the topic at hand ([51], p. 132, citations omitted). If a court does find a statute ambiguous under Chevron Step One, it must defer to any reasonable agency interpretation under the second prong of the Chevron inquiry (Chevron Step Two). In Chevron,