The APA exempts from notice and comment interpretative rules or general statements of policy. 5 U.S.C. § 553(b)(3)(A) (1994).
It is quite difficult to distinguish between substantive and interpretative rules. See Paralyzed Veterans of Am. v. D.C. Arena L.P., 117 F.3d 579, 587 (D.C. Cir. 1997); American Mining Congress v. Mine Safety & Health Admin., 302 U.S. App. D.C. 38, 995 F.2d 1106, 1108-09 (D.C. Cir. 1993); see also American Hosp. Ass'n v. Bowen, 266 U.S. App. D.C. 190, 834 F.2d 1037, 1045 (D.C. Cir. 1987) ('spectrum between a clearly interpretive rule and a clearly substantive one is a hazy continuum'); General Motors Corp. v. Ruckelshaus, 239 U.S. App. D.C. 408, 742 F.2d 1561, 1565 (D.C. Cir. 1984) (en banc) ('the distinction between legislative and interpretative rules is enshrouded in considerable smog') (citation omitted). Further confusing the matter is the tendency of courts and litigants to lump interpretative rules and policy statements together in contrast to substantive rules, a tendency to which we have ourselves succumbed on occasion. See Community Nutrition Inst. v. Young, 260 U.S. App. D.C. 294, 818 F.2d 943, 946 (D.C. Cir. 1987). That causes added confusion because interpretative ...