Opinion for the Court filed by Circuit Judge SILBERMAN.
SILBERMAN, Circuit Judge:
Appellants Syncor International Corporation, American College of Nuclear Physicians, Society of Nuclear Medicine, and American Pharmaceutical Association (collectively, Syncor) appeal the district court's decision that FDA's 1995 "Notice," entitled "Regulation of Positron Emission Tomography Radiopharmaceutical Drug Products; Guidance; Public Workshop," was a "non-substantive" rule not subject to notice and comment rulemaking. We reverse.
Positron emission tomography (PET) is a diagnostic imaging method that uses a subset of radioactive pharmaceuticals, called PET drugs, to determine biochemistry, physiology, anatomy, and pathology within various body organs and tissues by measuring the concentration of radioactivity in a targeted area of the body. The active component of PET drugs is a positron-emitting isotope.
On February 25, 1995, FDA announced that PET radiopharmaceuticals "should be regulated" under the drug provisions of the Federal Food, Drug, and Cosmetic Act.
FDA indicated that its 1995 publication was to supersede its prior 1984 publication — directed at all nuclear pharmacies, not just those compounding PET radiopharmaceuticals
Syncor filed suit in the district court challenging FDA's 1995 publication. Syncor brought three claims, alleging that: (1) FDA lacked jurisdiction over PET drugs under the new drug provision of § 505 of the Act, which requires premarket approval for drugs introduced or delivered for introduction into interstate commerce, because PET drugs do not move in interstate commerce;
The APA exempts from notice and comment interpretative rules or general statements of policy. 5 U.S.C. § 553(b)(3)(A) (1994). Before the district court the FDA characterized its 1995 publication as merely "guidance" (a general statement of policy). The district judge disagreed, concluding that it was a rule, but an interpretative one. Here, FDA concedes that the publication is a "rule," and adopts the district court's conclusion. Syncor still contends that the publication is a substantive regulation.
We have long recognized that 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., 995 F.2d 1106, 1108-09 (D.C.Cir.1993); see also American Hosp. Ass'n v. Bowen, 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, 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
An interpretative rule, on the other hand, typically reflects an agency's construction of a statute that has been entrusted to the agency to administer. The legal norm is one that Congress has devised; the agency does not purport to modify that norm, in other words, to engage in lawmaking. To be sure, since an agency's interpretation of an ambiguous statute is entitled to judicial deference under Chevron,
We should note, in order to be complete (although this variation is not implicated in the case before us), that an interpretative rule can construe an agency's substantive regulation as well as a statute. See Paralyzed Veterans, 117 F.3d at 586; American Mining Congress, 995 F.2d at 1107-08. In that event, the interpretative rule is, in a sense, even more binding on the agency because its modification, unlike a modification of an interpretative rule construing a statute, will likely require a notice and comment procedure. Otherwise, the agency could evade its notice and comment
A substantive rule has characteristics of both the policy statement and the interpretative rule; it is certainly in part an exercise of policy, and it is a rule. But the crucial distinction between it and the other two techniques is that a substantive rule modifies or adds to a legal norm based on the agency's own authority. That authority flows from a congressional delegation to promulgate substantive rules, to engage in supplementary lawmaking. And, it is because the agency is engaged in lawmaking that the APA requires it to comply with notice and comment.
It is apparent to us, in light of the foregoing discussion, that FDA's 1995 publication is not an interpretative rule. It does not purport to construe any language in a relevant statute or regulation; it does not interpret anything. Instead, FDA's rule uses wording consistent only with the invocation of its general rulemaking authority to extend its regulatory reach. See American Mining Congress, 995 F.2d at 1112. The publication is entitled "Regulation of Positron Emission Tomography Radiopharmaceutical Drug Products." In the text, FDA explained that "as [PET] technology has advanced, questions have been raised about the most appropriate approach to regulation of PET radiopharmaceuticals." And then FDA stated, "[h]aving considered the available information, including that presented to the agency at the hearing and in written materials, FDA has concluded that radiopharmaceuticals should be regulated under the drug provisions of the Federal Food, Drug, and Cosmetic Act."
FDA made a careful, considered decision not to exercise the full extent of its regulatory authority — whatever that may be — over nuclear pharmacies in 1984. In its "Nuclear Pharmacy Guideline; Criteria for Determining When to Register as a Drug Establishment," it said that "the criteria for registration as a drug establishment for nuclear pharmacies should be the same as those for traditional pharmacies" under the pharmacy exemption of § 510(g)(1) of the Act. And, therefore, "in a situation where the nuclear pharmacy is operating within applicable local laws regulating the practice of pharmacy and only prepares and dispenses a radioactive drug upon receipt of a `valid prescription,' the pharmacy exemption clearly applies." Persons who simply operated an accelerator in the course of compounding radioactive drugs to be dispensed under a prescription specifically were found not to be required to register.
Syncor tells us, and FDA does not dispute, that PET manufacturers today operate within applicable local laws governing pharmacy, and only prepare and dispense PET radiopharmaceuticals under a prescription, as they did in 1984. FDA does claim that PET technology has advanced and that PET has many more applications today than it did in 1984. And, after "[h]aving considered the available information," FDA has concluded, by way of its challenged rule, that PET manufacturers "should be regulated." Their activities — which clearly fell within the scope of the regular course of the practice of the profession of pharmacy in 1984 — are thought no longer to fall within that scope. This is not a change in interpretation or in enforcement policy, but rather, is fundamentally new regulation. The reasons FDA has advanced for its rule — advancement in PET technology, the expansion of procedures in which PET is used, and the unique nature of PET radiopharmaceuticals — are exactly the sorts of changes in fact and circumstance which notice and comment rulemaking is meant to inform. Cf. Bechtel v. FCC, 957 F.2d 873, 881 (D.C.Cir.1992) (changes in factual and legal circumstances may impose upon an agency the obligation to reconsider settled policy or explain its failure to do so); American Horse Protection Ass'n v. Lyng, 812 F.2d 1, 5 (D.C.Cir.1987) (rulemaking may be required on the basis of a radical change in
The FDA nevertheless focuses on American Mining Congress, in which, recognizing that an agency often has an option to proceed through adjudication, we warned against construing the interpretative rule exception to the APA's notice and comment provisions "so narrowly as to drive agencies into pure [adjudicatory] ad hocery — an ad hocery, moreover, that affords less notice, or less convenient notice, to affected parties." American Mining Congress, 995 F.2d at 1112. Accordingly, we identified four factors, any one of which, if present, would identify a supposed interpretative rule as really legislative.
The government contends that the rule in question qualifies as an interpretative rule, under that factor, because in the absence of its issuance the government could have proceeded to enforce regulatory requirements against manufacturers of PET drugs. In the past, pursuant to FDA's 1984 Guideline, those requirements were merely "deferred." The government does not clearly explain what it means by "deferred," but seems to suggest that it exercised enforcement discretion in not asserting regulatory authority over appellants until 1995, and therefore simply is reversing that discretionary decision. The obvious difficulty with the government's argument is that it is supportive of a claim that the rule was really a policy statement — a claim which the government abandoned on appeal. As we have said, enforcement discretion is relevant in determining whether an agency intended to bind itself, and therefore, in determining whether a pronouncement is a legislative rule or a general statement of policy, but "tells one little about whether a rule is interpretive." American Mining Congress, 995 F.2d at 1111.
In any event, we think the government misreads American Mining Congress. We never suggested in that case that a rule that does not purport to interpret any language in a statute or regulation could be thought an interpretative rule.
Accordingly, we reverse and remand to the district court with instructions to enter summary judgment in Syncor's favor, and to vacate FDA's rule as not in accordance with law. The district court should also dismiss Syncor's substantive claims without prejudice.
With the three rules at issue in that case, the Mine Safety & Health Administration purported to be interpreting the term "diagnosis" as used in its own substantive regulation that had been adopted by notice and comment rulemaking. We note, however, that one or more of these rules might have been, at least in part, policy statements. See id. at 1108.