In Building & Construction Trades Department, AFLCIO v. Brock (Asbestos), 838 F.2d 1258 , 1271 (D.C. Cir. 1988), a union challenged OSHAs (Occupational Health and Safety Act) decision to trigger some employer duties at the action level and others at the permissible exposure limit (PEL). The union argued that it was feasible to trigger many of the latter duties at the action level rather than at the PEL, and that the Secretary therefore erred in not so providing. 838 F.2d at 1274. OSHA had defended its decision as reasonable priority-setting that permitted employers to concentrate their resources on those employees and workplace conditions with the potential for high asbestos exposures. Id. (quoting Occupational Exposure to Asbestos, 51 Fed. Reg. 22,612, 22,707 (June 20, 1986)). The Court was skeptical of the agencys asserted justification because it did not explicitly relate to either feasibility or lack of benefit. Id. Nonetheless, the court rejected the unions challenge. As the Court explained, the force of the evidence and argument that OSHA must offer to defend its choice will vary with the force of the proponents evidence and argument. Id. at 1271.