In AFL-CIO v. OSHA, 965 F.2d 962 (11th Cir. 1992), the Court reviewed OSHA's Air Contaminants Standard, a comprehensive set of permissible exposure limits ("PELs") for 428 toxic substances. The notice of proposed rulemaking for the Air Contaminants Standard proposed to issue new or revised PELs for a number of substances, but "limited the scope of the rulemaking to those substances for which a private standard-setting organization recommended limits that were either new or more protective than the existing PELs." Id. at 969 (citing the notice of proposed rulemaking). After issuance of the Air Contaminants Standard, industry and labor unions attacked it from both sides the Court. The unions in AFL-CIO argued that by limiting the rulemaking to those substances that either (1) had no existing PEL, or (2) for which the standard-setting organization had recommended a limit more protective than the existing PEL, OSHA had violated the command of the OSH Act that it set standards " 'which most adequately assure . . . that no employee will suffer material impairment of health or functional capacity.' " Id. at 984 (quoting 29 U.S.C. 655(b)(5) (alterations in original)). The court rejected this argument: We do not find a requirement that OSHA include all possible substances in one rulemaking. OSHA has never claimed that the Air Contaminants Standard constituted the entire universe of substances needing regulation, and it seems reasonable that some limit needed to be set as to what substances could be considered in this rulemaking. The list of the standard-setting organization's recommendations is a rational choice as the source for that limitation. Those recommendations are well known to industry and the safety and health community. Therefore, we find that the agency's choice to so limit this rulemaking is a valid exercise of OSHA's authority to set priorities for rulemaking. Id. The union brought a separate challenge to a decision by OSHA "to defer issuing standards for monitoring and medical surveillance of the new PELs until a laterrulemaking." Id. at 985. Under 6(b)(7) of the OSH Act, occupational safety and health standards are required to provide for "monitoring or measuring employee exposure," and to prescribe medical examinations and tests, where appropriate. 29 U.S.C. 665(b)(7). T he union claimed that OSHA violated this requirement by promulgating the Air Contaminants Standard without simultaneously promulgating monitoring and medical surveillance rules with respect to that standard. We also dismissed this argument, holding that this was "purely a matter of regulatory priority" with respect to which the agency had ample discretion. AFL-CIO, 965 F.2d at 985. Thus, OSHA was permitted to wait and address monitoring and medical surveillance at another point.