delivered the opinion of the Court.

The Freedom of Information Act (FOIA), 5 U. S. C. § 552, requires federal agencies to make Government records available to the public, subject to nine exemptions for specific categories of material. This case concerns the scope of Exemption 2, which protects from disclosure material that is “related solely to the internal personnel rules and practices of an agency.” § 552(b)(2). Respondent Department of the Navy (Navy or Government) invoked Exemption 2 to deny[*565] a FOIA request for data and maps used to help store explosives at a naval base in Washington State. We hold that Exemption 2 does not stretch so far.

I

Congress enacted FOIA to overhaul the public-disclosure section of the Administrative Procedure Act (APA), 5 U. S. C. §1002 (1964 ed.). That section of the APA “was plagued with vague phrases” and gradually became more “a withholding statute than a disclosure statute.” EPA v. Mink, 410 U. S. 73, 79 (1973). Congress intended FOIA to “permit access to official information long shielded unnecessarily from public view.” Id., at 80. FOIA thus mandates that an agency disclose records on request, unless they fall within one of nine exemptions. These exemptions are “explicitly made exclusive,” id., at 79, and must be “narrowly construed,” FBI v. Abramson, 456 U. S. 615, 630 (1982).

At issue here is Exemption 2, which shields from compelled disclosure documents “related solely to the internal personnel rules and practices of an agency.” § 552(b)(2). Congress enacted Exemption 2 to replace the APA’s exemption for “any matter relating solely to the internal management of an agency,” 5 U. S. C. § 1002 (1964 ed.). Believing that the “sweep” of the phrase “internal management” had led to excessive withholding, Congress drafted Exemption 2 “to have a narrower reach.” Department of Air Force v. Rose, 425 U. S. 352, 362-363 (1976).

We considered the extent of that reach in Department of Air Force v. Rose. There, we rejected the Government’s invocation of Exemption 2 to withhold case summaries of honor and ethics hearings at the United States Air Force Academy. The exemption, we suggested, primarily targets material concerning employee relations or human resources: “‘use of parking facilities or regulations of lunch hours, statements of policy as to sick leave, and the like.’” Id., at 363 (quoting S. Rep. No. 813, 89th Cong., 1st Sess., 8 (1965)[*566] (hereinafter S. Rep.)); see Rose, 425 U. S., at 367. “[T]he general thrust” of Exemption 2, we explained, “is simply to relieve agencies of the burden of assembling and maintaining [such information] for public inspection.” Id., at 369. We concluded that the case summaries did not fall within the exemption because they “d[id] not concern only routine matters” of “merely internal significance.” Id., at 370. But we stated a possible caveat to our interpretation of Exemption 2: That understanding of the provision’s coverage governed, we wrote, “at least where the situation is not one where disclosure may risk circumvention of agency regulation.” Id., at 369.

In Crooker v. Bureau of Alcohol, Tobacco & Firearms, 670 F. 2d 1051 (1981) (en banc), the D. C. Circuit converted this caveat into a new definition of Exemption 2’s scope. Crooker approved the use of Exemption 2 to shield a manual designed to train Government agents in law enforcement surveillance techniques. The D. C. Circuit noted that it previously had understood Exemption 2 to “refe[r] only to ‘pay, pensions, vacations, hours of work, lunch hours, parking[,] etc.’” Id., at 1056 (quoting Jordan v. Department of Justice, 591 F. 2d 753, 763 (1978)). But the court now thought Exemption 2 should also cover any “predominantly internal” materials,^[1] Crooker, 670 F. 2d, at 1056-1057, whose disclosure would “significantly ris[k] circumvention of agency regulations or statutes,” id., at 1074. This construction of Exemption 2, the court reasoned, flowed from FOIA’s “overall design,” its legislative history, “and even common sense,” because Congress could not have meant to “enac[t] a statute[*567] whose provisions undermined . . . the effectiveness of law enforcement agencies.” Ibid.

In the ensuing years, three Courts of Appeals adopted the D. C. Circuit’s interpretation of Exemption 2. See 575 F. 3d 959, 965 (CA9 2009) (case below); Massey v. FBI, 3 F. 3d 620, 622 (CA2 1993); Kaganove v. EPA, 856 F. 2d 884, 889 (CA7 1988).^[2] And that interpretation spawned a new terminology: Courts applying the Crooker approach now refer to the “Low 2” exemption when discussing materials concerning human resources and employee relations, and to the “High 2” exemption when assessing records whose disclosure would risk circumvention of the law. See, e. g., 575 F. 3d, at 963; Schiller v. NLRB, 964 F. 2d 1205, 1208 (CADC 1992). Congress, as well, took notice of the D. C. Circuit’s decision, borrowing language from Crooker to amend Exemption 7(E) when next enacting revisions to FOIA. The amended version of Exemption 7(E) shields certain “records or information compiled for law enforcement purposes” if their disclosure “could reasonably be expected to risk circumvention of the law.” § 552(b)(7)(E); see Freedom of Information Reform Act of 1986, § 1802(a), 100 Stat. 3207-49.

II

The FOIA request at issue here arises from the Navy’s operations at Naval Magazine Indian Island, a base in Puget[*568] Sound, Washington. The Navy keeps weapons, ammunition, and explosives on the island. To aid in the storage and transport of these munitions, the Navy uses data known as Explosive Safety Quantity Distance (ESQD) information. 575 F. 3d, at 962. ESQD information prescribes “minimum separation distances” for explosives and helps the Navy design and construct storage facilities to prevent chain reactions in case of detonation. Ibid. The ESQD calculations are often incorporated into specialized maps depicting the effects of hypothetical explosions. See, e. g., App. 52.

In 2003 and 2004, petitioner Glen Milner, a Puget Sound resident, submitted FOIA requests for all ESQD information relating to Indian Island. 575 F. 3d, at 962. The Navy refused to release the data, stating that disclosure would threaten the security of the base and surrounding community. In support of its decision to withhold the records, the Navy invoked Exemption 2. Ibid.3

The District Court granted summary judgment to the Navy, and the Court of Appeals affirmed, relying on the High 2 interpretation developed in Crooker. 575 F. 3d, at 963. The Court of Appeals explained that the ESQD information “is predominantly used for the internal purpose of instructing agency personnel on how to do their jobs.” Id., at 968. And disclosure of the material, the court determined, “would risk circumvention of the law” by “pointing] out the best targets for those bent on wreaking havoc” — for example, “[a] terrorist who wished to hit the most damaging target.” Id., [*569] at 971. The ESQD information, the court concluded, therefore qualified for a High 2 exemption. Ibid.

We granted certiorari in light of the Circuit split respecting Exemption 2’s meaning, 561 U. S. 1024 (2010), and we now reverse.

Ill

Our consideration of Exemption 2’s scope starts with its text. See, e. g., Park ’N Fly, Inc. v. Dollar Park & Fly, Inc., 469 U. S. 189, 194 (1985) (“Statutory construction must begin with the language employed by Congress and the assumption that the ordinary meaning of that language accurately expresses the legislative purpose”). Judicial decisions since FOIA’s enactment have analyzed and reanalyzed the meaning of the exemption. But comparatively little attention has focused on the provision’s 12 simple words: “related solely to the internal personnel rules and practices of an agency.”

The key word in that dozen — the one that most clearly marks the provision’s boundaries — is “personnel.” When used as an adjective, as it is here to modify “rules and practices,” that term refers to human resources matters. “Personnel,” in this common parlance, means “the selection, placement, and training of employees and ... the formulation of policies, procedures, and relations with [or involving] employees or their representatives.” Webster’s Third New International Dictionary 1687 (1966) (hereinafter Webster’s). So, for example, a “personnel department” is “the department of a business firm that deals with problems affecting the employees of the firm and that usually interviews applicants for jobs.” Random House Dictionary 1075 (1966) (hereinafter Random House). “Personnel management” is similarly “the phase of management concerned with the engagement and effective utilization of manpower to obtain optimum efficiency of human resources.” Webster’s 1687. And a “personnel agency” is “an agency for placing employable persons in jobs; employment agency.” Random House 1075.

[*570] FOIA itself provides an additional example in Exemption 6. See Ratzlaf v. United States, 510 U. S. 135, 143 (1994) (“A term appearing in several places in a statutory text is generally read the same way each time it appears”). That exemption, just a few short paragraphs down from Exemption 2, protects from disclosure “personnel and medical files and similar files the disclosure of which would constitute a clearly unwarranted invasion of personal privacy.” § 552(b)(6). Here too, the statute uses the term “personnel” as a modifier meaning “human resources.” See Tr. of Oral Arg. 32 (“[The Court:] It’s [an] H. R. file, right? [The Government:] That’s generally true”). As we recognized in Rose, “the common and congressional meaning of... 'personnel file’ ” is the file “showing, for example, where [an employee] was born, the names of his parents, where he has lived from time to time, his . . . school records, results of examinations, [and] evaluations of his work performance.” 425 U. S., at 377. It is the file typically maintained in the human resources office — otherwise known (to recall an example offered above) as the “personnel department.” Ibid.

Exemption 2 uses “personnel” in the exact same way. An agency’s “personnel rules and practices” are its rules and practices dealing with employee relations or human resources. The D. C. Circuit, in a pre-Crooker decision, gave as examples “matters relating to pay, pensions, vacations, hours of work, lunch hours, parking, etc.” Jordan, 591 F. 2d, at 763; see supra, at 566. That “etc.” is important; we doubt any court could know enough about the Federal Government’s operations to formulate a comprehensive list. But all the rules and practices referenced in Exemption 2 share a critical feature: They concern the conditions of employment in federal agencies — such matters as hiring and firing, work rules and discipline, compensation and benefits.^[4] Courts in[*571] practice have had little difficulty identifying the records that qualify for withholding under this reading: They are what now commonly fall within the Low 2 exemption. Our construction of the statutory language simply makes clear that Low 2 is all of 2 (and that High 2 is not 2 at all, see infra, at 573-577).

The statute’s purpose reinforces this understanding of the exemption. We have often noted “the Act’s goal of broad disclosure” and insisted that the exemptions be “given a narrow compass.” Department of Justice v. Tax Analysts, 492 U. S. 136, 151 (1989); see Department of Interior v. Klamath Water Users Protective Assn., 532 U. S. 1, 7-8 (2001).^[5] This practice of “constru[ing] FOIA exemptions narrowly,” Department of Justice v. Landano, 508 U. S. 165, 181 (1993), stands on especially firm footing with respect to Exemption 2. As described earlier, Congress worded that provision to hem in the prior APA exemption for “any matter relating solely to the internal management of an agency,” which agencies had used to prevent access to masses of documents. See Rose, 425 U. S., at 362. We would ill-serve[*572] Congress’s purpose by construing Exemption 2 to reauthorize the expansive withholding that Congress wanted to halt. Our reading instead gives the exemption the “narrower reach” Congress intended, id., at 363, through the simple device of confining the provision’s meaning to its words.

The Government resists giving “personnel” its plain meaning on the ground that Congress, when drafting Exemption 2, considered but chose not to enact language exempting “internal employment rules and practices.” Brief for Respondent 30-34, and n. 11 (internal quotation marks omitted). This drafting history, the Navy maintains, proves that Congress did not wish “to limit the Exemption to employment-related matters,” id., at 31, even if the adjective “personnel” conveys that meaning in other contexts, id., at 41. But we think the Navy’s evidence insufficient: The scant history concerning this word change as easily supports the inference that Congress merely swapped one synonym for another. Cf. Mead Corp. v. Tilley, 490 U. S. 714, 723 (1989) (noting with respect to the “unexplained disappearance of one word from an unenacted bill” that “mute intermediate legislative maneuvers are not reliable” aids to statutory interpretation (internal quotation marks omitted)). Those of us who make use of legislative history believe that clear evidence of congressional intent may illuminate ambiguous text. We will not take the opposite tack of allowing ambiguous legislative history to muddy clear statutory language.

Exemption 2, as we have construed it, does not reach the ESQD information at issue here. These data and maps calculate and visually portray the magnitude of hypothetical detonations. By no stretch of imagination do they relate to “personnel rules and practices,” as that term is most naturally understood. They concern the physical rules governing explosives, not the workplace rules governing sailors; they address the handling of dangerous materials, not the treatment of employees. The Navy therefore may not use Exemption 2, interpreted in accord with its plain meaning to[*573] cover human resources matters, to prevent disclosure of the requested maps and data.

IV

The .Government offers two alternative readings of Exemption 2 to support withholding the ESQD information. We cannot square either with the statute.

A

The Navy first encourages us to adopt the construction of Exemption 2 pioneered by Crooker, which shields material not only if it meets the criteria set out above (Low 2), but also if it is “predominant[ly] interna[l]” and its “disclosure would significantly risk[ ] circumvention of federal agency functions” (High 2). Brief for Respondent 41 (internal quotation marks omitted). The dissent, too, favors this reading of the statute. Post, at 585. But the Crooker interpretation, as already suggested, suffers from a patent flaw: It is disconnected from Exemption 2’s text. The High 2 test (in addition to substituting the word “predominantly” for “solely,” see n. 1, supra) ignores the plain meaning of the adjective “personnel,” see supra, at 569-572 and this page, and adopts a circumvention requirement with no basis or referent in Exemption 2’s language. Indeed, the only way to arrive at High 2 is by taking a red pen to the statute — “cutting out some” words and “pasting in others” until little of the actual provision remains. Elliott v. Department of Agriculture, 596 F. 3d 842, 845 (CADC 2010). Because this is so, High 2 is better labeled “Non 2” (and Low 2 ... just 2).

In support of its text-light approach to the statute, the Government relies primarily on legislative history, placing particular emphasis on the House Report concerning FOIA. See Brief for Respondent 33-38. A statement in that Report buttresses the High 2 understanding of the exemption and, indeed, specifically rejects the Low 2 construction. According to the Report: “Operating rules, guidelines, and manuals of procedure for Government investigators or exam[*574]iners would be exempt from disclosure [under Exemption 2], but this exemption would not cover . . . employee relations and working conditions and routine administrative procedures.” H. R. Rep. No. 1497, 89th Cong., 2d Sess., 10 (1966). But the Senate Report says exactly the opposite, explaining in support of a Low 2 interpretation that the phrase “internal personnel rules and practices of an agency” means “rules as to personnel's use of parking facilities or regulation of lunch hours, statements of policy as to sick leave, and the like.” S. Rep., at 8.^[6] In Rose, we gave reasons for thinking the Senate Report the more reliable of the two. See 425 U. S., at 366. But the more fundamental point is what we said before: Legislative history, for those who take it into account, is meant to clear up ambiguity, not create it. See supra, at 572; Wong Yang Sung v. McGrath, 339 U. S. 33, 49 (1950) (declining to consult legislative history when that “history is more conflicting than the text is ambiguous”). When presented, on the one hand, with clear statutory language and, on the other, with dueling committee reports, we must choose the language.

The Government also advances, in support of Crooker’s High 2 approach, an argument based on subsequent legislative action. Congress, the Government notes, amended Exemption 7(E) in 1986 to cover law enforcement records whose production “would disclose techniques and procedures for law enforcement investigations or prosecutions, or would disclose guidelines for law enforcement investigations or prosecutions if such disclosure could reasonably be expected to risk circumvention of the law.” § 552(b)(7)(E). That amendment, the Government contends, codified Crooker’s “circumvention of the law” standard and, in so doing, ratified[*575] Crooker’s holding. Brief for Respondent 42-43. The dissent likewise counts as significant that Congress “t[ook] note” of Crooker in revising FOIA. Post, at 592; see post, at 586.

But the Government and the dissent neglect the key feature of the 1986 amendment: Congress modified not Exemption 2 (the subject of Crooker), but instead Exemption 7(E). And the Crooker construction of Exemption 2 renders Exemption 7(E) superfluous and so deprives that amendment of any effect. See, e. g., TRW Inc. v. Andrews, 534 U. S. 19, 31 (2001) (noting canon that statutes should be read to avoid making any provision “superfluous, void, or insignificant” (internal quotation marks omitted)). We cannot think of any document eligible for withholding under Exemption 7(E) that the High 2 reading does not capture: The circumvention standard is the same, and the law enforcement records listed in Exemption 7(E) are “predominantly internal.” So if Congress had agreed with Crooker’s reading of Exemption 2, it would have had no reason to alter Exemption 7(E). In that event, Congress would either have left the statute alone (on the theory that Crooker would do the necessary work) or would have amended Exemption 2 specifically to ratify Crooker. The decision instead to amend Exemption 7(E) suggests that Congress approved the circumvention standard only as to law enforcement materials, and not as to the wider set of records High 2 covers. Perhaps this legislative action does not show that Congress affirmatively disagreed with Crooker; maybe Congress was agnostic about whether the circumvention standard should apply to other records. But one thing is clear: The 1986 amendment does not ratify, approve, or otherwise signal agreement with Crooker’s interpretation of Exemption 2. This argument therefore cannot save the High 2 construction.

The dissent offers one last reason to embrace High 2, and indeed stakes most of its wager on this argument. Crooker, the dissent asserts, “has been consistently relied upon and followed for 30 years” by other lower courts. Post, at 592;[*576] see post, at 585-586. But this claim, too, trips at the starting gate. It would be immaterial even if true, because we have no warrant to ignore clear statutory language on the ground that other courts have done so. And in any event, it is not true. Prior to Crooker, three Circuits adopted the reading of Exemption 2 we think right, and they have not changed their minds. See n. 2, supra.7 Since Crooker, three other Circuits have accepted the High 2 reading. See supra, at 567. One Circuit has reserved judgment on the High 2-Low 2 debate. See Audubon Soc. v. United States Forest Serv., 104 F. 3d 1201, 1203-1204 (CA10 1997). And the rest have not considered the matter. (No one should think Crooker has been extensively discussed or debated in[*577] the Courts of Appeals. In the past three decades, Crooker’s analysis of Exemption 2 has been cited a sum total of five times in federal appellate decisions outside the D. C. Circuit — on average, once every six years.) The result is a 4-to-3 split among the Circuits.^[8] We will not flout all usual rules of statutory interpretation to take the side of the bare majority.

B

Presumably because Crooker so departs from Exemption 2’s language, the Government also offers another construction, which it says we might adopt “on a clean slate,” “based on the plain text.. . alone.” Brief for Respondent 15. On this reading, the exemption “encompasses records concerning an agency’s internal rules and practices for its personnel to follow in the discharge of their governmental functions.” Id., at 20; see also id., at 13-14 (Exemption 2 “applies generally to matters concerning internal rules and practices to guide agency personnel in performing their duties”). According to the Government, this interpretation makes sense because “the phrase 'personnel rules and practices of an agency’ is logically understood to mean an agency’s rules and practices for its personnel.” Id., at 20 (emphasis added).

But the purported logic in the Government’s definition eludes us. We would not say, in ordinary parlance, that a “personnel file” is any file an employee uses, or that a “personnel department” is any department in which an employee[*578] serves. No more would we say that a “personnel rule or practice” is any rule or practice that assists an employee in doing her job. The use of the term “personnel” in each of these phrases connotes not that the file or department or practice/rule is for personnel, but rather that the file or department or practice/rule is about personnel — i. e., that it relates to employee relations or human resources. This case well illustrates the point. The records requested, as earlier noted, are explosives data and maps showing the distances that potential blasts travel. This information no doubt assists Navy personnel in storing munitions. But that is not to say that the data and maps relate to “personnel rules and practices.” No one staring at these charts of explosions and using ordinary language would describe them in this manner.

Indeed, the Government’s “clean slate” construction reaches such documents only by stripping the word “personnel” of any real meaning. Under this interpretation, an agency’s “internal personnel rules and practices” appears to mean all its internal rules and practices. That is because agencies necessarily operate through personnel, and so all their internal rules and practices are for personnel. The modifier “personnel,” then, does no modifying work; it does not limit the class of internal rules and practices that Exemption 2 covers. What is most naturally viewed as the provision’s key word — the term that ought to define its scope — does nothing more than state the truism that in an agency it is “personnel” who follow internal rules and practices.

And this odd reading would produce a sweeping exemption, posing the risk that FOIA would become less a disclosure than “a withholding statute.” Mink, 410 U. S., at 79. Many documents an agency generates in some way aid employees in carrying out their responsibilities. If Exemption 2 were to reach all these records, it would tend to engulf other FOIA exemptions, rendering ineffective the limitations Congress placed on their application. Exemption 7,[*579] for example, shields records compiled for law enforcement purposes, but only if one of six specified criteria is met. § 552(b)(7). Yet on the Government’s view, an agency could bypass these restrictions by invoking Exemption 2 whenever law enforcement records guide personnel in performing their duties. Indeed, an agency could use Exemption 2 as an all-purpose back-up provision to withhold sensitive records that do not fall within any of FOIA’s more targeted exemptions.^[9]

Interpreted in this way, Exemption 2 — call it “Super 2” now — would extend, rather than narrow, the APA’s former exemption for records relating to the “internal management of an agency.” 5 U. S. C. § 1002 (1964 ed.). We doubt that even the “internal management” provision, which Congress thought allowed too much withholding, see supra, at 565, would have protected all information that guides employees in the discharge of their duties, including the explosives data and maps in this case. And perhaps needless to say, this reading of Exemption 2 violates the rule favoring narrow[*580] construction of FOIA exemptions. See, e. g., Abramson, 456 U. S., at 630; Rose, 425 U. S., at 361. Super 2 in fact has no basis in the text, context, or purpose of FOIA, and we accordingly reject it.

V

Although we cannot interpret Exemption 2 as the Government proposes, we recognize the strength of the Navy’s interest in protecting the ESQD data and maps and other similar information. The Government has informed us that “[pjublicly disclosing the [ESQD] information would significantly risk undermining the Navy’s ability to safely and securely store military ordnance,” Brief for Respondent 47, and we have no reason to doubt that representation. The Ninth Circuit similarly cautioned that disclosure of this information could be used to “wrea[k] havoc” and “make catastrophe more likely.” 575 F. 3d, at 971. Concerns of this kind — a sense that certain sensitive information should be exempt from disclosure — in part led the Crooker court to formulate the High 2 standard. See 670 F. 2d, at 1074 (contending that “common sense” supported the High 2 interpretation because Congress would not have wanted FOIA to “under-min[e] . . . the effectiveness of law enforcement agencies”). And we acknowledge that our decision today upsets three decades of agency practice relying on Crooker, and therefore may force considerable adjustments.

We also note, however, that the Government has other tools at hand to shield national security information and other sensitive materials. Most notably, Exemption 1 of FOIA prevents access to classified documents. § 552(b)(1); see 575 F. 3d, at 980 (W. Fletcher, J., dissenting) (Exemption 1 is “specifically designed to allow government agencies to withhold information that might jeopardize our national security”). The Government generally may classify material even after receiving a FOIA request, see Exec. Order No. 13526, § 1.7(d), 75 Fed. Reg. 711 (2009); an agency therefore may wait until that time to decide whether the dangers[*581] of disclosure outweigh the costs of classification. See Tr. of Oral Arg. 29-30. Exemption 3 also may mitigate the Government’s security concerns. That provision applies to records that any other statute exempts from disclosure, § 552(b)(3) (2006 ed., Supp. IV), thus offering Congress an established, streamlined method to authorize the withholding of specific records that FOIA would not otherwise protect. And Exemption 7, as already noted, protects “information compiled for law enforcement purposes” that meets one of six criteria, including if its release “could reasonably be expected to endanger the life or physical safety of any individual.” §552(b)(7)(F) (2006 ed.). The Navy argued below that the ESQD data and maps fall within Exemption 7(F), see n. 3, supra, and that claim remains open for the Ninth Circuit to address on remand.

If these or other exemptions do not cover records whose release would threaten the Nation’s vital interests, the Government may of course seek relief from Congress. See Tr. of Oral Arg. 48. All we hold today is that Congress has not enacted the FOIA exemption the Government desires. We leave to Congress, as is appropriate, the question whether it should do so.

VI

Exemption 2, consistent with the plain meaning of the term “personnel rules and practices,” encompasses only records relating to issues of employee relations and human resources. The explosives maps and data requested here do not qualify for withholding under that exemption. We therefore reverse the judgment of the Court of Appeals and remand the case for further proceedings consistent with this opinion.

It is so ordered.