This is an appeal from the trial judge’s grant of the government’s Motion for Summary Judgment based on a detailed affidavit in lieu of an in camera inspection of requested documents under the Freedom of Information Act (FOIA), 5 U.S.C. § 552 (1976 & Supp. V 1981). Appellant, Center for Auto Safety (“the Center”) is a nonprofit consumer organization chartered under the laws of the District of Columbia for the purpose of improving the quality, safety, fuel efficiency and emissions controls of motor vehicles. It was founded in 1973 by Ralph Nader and Consumers Union. This ease arises from the trial court’s decision not to inspect 19 documents in camera that the Center had requested from the Environmental Protection Agency (EPA) under the FOIA. The documents concerned an EPA decision to accept a plan under which General Motors (GM) • would “offset” previously illegally high levels of auto emissions by lowering such levels in future car model years. This Court is asked to decide the circumstances under which a district court must conduct an in camera review of a small sample of documents in order to verify an agency’s assertions that factual material is “inextricably intertwined” with exempt deliberative portions of records. Specifically, the Center urges this Court to adopt a limited per se rule requiring the trial court to conduct an in camera review of documents claimed to be exempt under Exemption 5 of the FOIA.1 Because we find that adoption of such a per se rule would contravene the clear grant by Congress of broad discretion to trial judges in this matter, and because we find that the trial court did not abuse its discretion in this case, we affirm the trial court’s decision regarding in camera inspection.
Factual Background
After a large number of 1979 General Motors automobiles had been sold to the *18public, EPA tests revealed that each of more than half a million cars was emitting levels of nitrogen oxides in violation of the Clean Air Act, 42 U.S.C. § 7401 et seq. GM proposed offsetting the excess pollution by building its 1982 and 1983 cars to produce lower emissions standards than the law required. In August of 1982, the EPA approved such a plan.2
On August 5, 1982, the Center submitted an FOIA request to the EPA for all documents concerning the decision to accept the offset plan. J.A. 80. On September 9, 1982, EPA released some of the documents but withheld a number of documents under the belief that they were exempt from disclosure under Exemption 5, 5 U.S.C. § 552(b)(5). J.A. 83. The Center filed a timely administrative appeal which was not ruled upon within the 20 working days required under the FOIA. See 5 U.S.C. §§ 552(a)(6)(A), (C); J.A. 87. After this exhaustion of administrative remedies, the Center brought suit in the United States District Court for the District of Columbia.
By letter dated December 20, 1982, EPA notified the Center that the administrative appeal had been considered, and that EPA “no longer objects to disclosure of 32 documents in their entirety ... and of portions of 30 documents.” Brief for Defendant at Exhibit A. EPA enclosed these documents with the letter. EPA continued to withhold 53 documents. As to these 53 documents, with the exception of one document3, EPA maintained that they were “intra-agency communications and records of settlement negotiations which reflect EPA’s deliberative process” and therefore exempt under Exemption 5. Id.
Both parties moved for summary judgment with respect to the remaining documents. EPA asserted that all of the documents were “predecisional and deliberative in nature” and that “[a]ll segregable factual material contained in the documents” had been disclosed. J.A. 22, 23. In support of its Motion for Summary Judgment, EPA submitted an affidavit of Charles N. Freed, the Director of EPA’s Manufacturers Operations Division of the Office of Mobile Sources and a Vaughn Index4 listing the 53 documents being withheld. The Center opposed EPA’s motion and limited its arguments to 19 of the 53 remaining documents. In addition, the Center requested that the District Court examine those documents in camera.5 See Reply Brief of Plaintiff-Appellant at Exhibit II.
On January 27, 1983, the District Court denied the Center’s request for in camera review “due to the detailed explanatory material promptly supplied by the EPA.” J.A. 3-4. This appeal ensued.6
*19The Issue Concerning In Camera Inspection Is Properly Before This Court
Appellee argues that the issue of in camera inspection “was never raised by the appellant at the District Court.” Brief for Defendant-Appellee at p. 4, n. 3. More specifically, appellee claims that the request was based on grounds “entirely unrelated” to any need to verify that facts were inextricably intertwined with deliberative materials. Id. If that were the case, the issue could not be raised for the first time on this appeal. See, e.g., Miller v. Avirom, 384 F.2d 319, 321-22 (D.C.Cir.1967). Such is not the case here.
Upon review of the record below, the Court finds that the first request by the Center for in camera review appeared in its Reply Memorandum and Opposition to Defendant’s Cross-Motion For Summary Judgment. In that document, the Center informed the trial court that it would limit its arguments to only 19 of the 53 documents withheld, but specifically requested that “the Court review the remainder of the documents in camera to determine if the EPA description is complete and accurate.” Reply Memorandum at p. 2. This request is directly contrary to appellee’s contention that the Center requested the inspection only to discover “the extent that they may have advised the EPA Administrator that the offset remedial plan was legal.” Brief of Defendant-Appellee at p. 5. The descriptions of the documents supplied by the EPA included a statement that “[a]ll segregable factual material contained in the documents” had been disclosed. J.A. 22, 23. The Center's request for inspection clearly included a desire to have the Court determine whether that .statement was accurate.
Appellee’s position is further undermined by the transcript of the oral arguments on the cross-motions for summary judgment. With respect to a set of eight factual or technical documents prepared by experts at the agency, the Center asked the trial court “to look at them and see if the descriptions are accurate____” Reply Brief of Plaintiff-Appellant at Exhibit II, p. 6. With respect to an additional set of eleven legal documents, the Center requested the Court “to review those documents in camera to see what they say.” Id. at 4. Finally, in rebuttal argument, counsel for the Center told the Court:
... the descriptions of the documents we are seeking appear to contain factual material. At a minimum, they may contain segregable factual material.
We urge your honor to look at the documents and see if they give any reasons for that decision or if they contain the kind of factual material not protected by the deliberative process privilege.
Id. at 13-14.
Based upon these statements and requests made to the trial court, we conclude that a request for in camera inspection on the issue of whether non-exempt facts appeared in the documents was properly made below, and is thus a proper issue for us to address on appeal.
Appellee also argues that this case is moot because all of the documents containing factual information have been released by Congress. Specifically, EPA claims that it withheld inextricably intertwined facts from only one document (Document 25) and since that document was made public on May 9, 1983, the present case is moot. Appellee is correct in pointing out that “once the records are produced [in an FOIA case] the substance of the controversy disappears and becomes moot since the disclosure the suit seeks has already been made.” Crooker v. State Department, 628 F.2d 9, 10 (D.C.Cir.1980); Carlisle Tire and Rubber Co. v. Customs Service, 663 F.2d 210 (D.C.Cir.1980) (when documents were released, any case or controversy regarding them evaporated); 5 U.S.C. § 552(a)(4)(B) (1976). We cannot agree, however, that this case is moot.
As noted before, the record is clear that the Center requested in camera inspection for nineteen (19) different documents. One of the major concerns of the Center was that segregable factual materi*20al could have been in these documents, but not released by the EPA. On May 9, 1983, Congress released only four of the documents the Center was concerned about. While this case is certainly moot with respect to those four (4) documents released by Congress, it is not moot with respect to the other fifteen (15) documents that the district court refused to examine in camera. The appellant has raised an important issue concerning the proper role of such inspections. Neither the importance of the issue nor the existence of a controversy is diminished when four of nineteen documents are released. Appellants still have a viable claim concerning the propriety of the trial judge’s refusal to examine the remaining 15 documents.
The Use Of In Camera Inspections Is Discretionary, Not Mandatory
Appellant contends that the district court should have examined the documents at issue in camera to determine whether any portion of the materials consists of non-exempt, “reasonably segregable” information. It has long been the rule in this Circuit that non-exempt factual information in a document must be disclosed unless it is inextricably intertwined with exempt material. See e.g., Mead Data Central, Inc. v. Dept. of the Air Force, 566 F.2d 242, 260 (D.C.Cir.1977). In 1974, Congress expressly incorporated this requirement into the FOIA which now provides that “[a]ny reasonably segregable portion of a record shall be provided ... after deletion of the portions which are exempt____” 5 U.S.C. § 522(b) (1976).
Appellant urges this Court to adopt a per se rule that trial courts must use in camera inspection where the agency claims that it is withholding factual material because such material is inextricably intertwined with exempt deliberative material under Exemption 5. Additionally, appellant narrows its proposed rule to require the court to review only a “small sample” of the withheld documents in order to insure the accuracy of agency affidavits and Vaughn Indices. Brief of Plaintiff-Appellant at p. 16. However, upon review of the plain language of the FOIA, the legislative history, and the relevant caselaw, it becomes apparent that Congress intended to impose no mandates upon the trial court, but instead leave the decision of whether to conduct in camera inspection to the broad discretion of the trial judge.
In 1974, Congress amended the FOIA and invested the district court with discretion to conduct in camera inspections without the necessity of relying upon agency affidavits. The District Court is required to determine FOIA exemption claims “de novo” and “may examine the contents of such agency records in camera ...” 5 U.S.C. § 552(a)(4)(B) (emphasis added). Thus, the plain words of the FOIA impose no mandatory obligation on the district court to review the actual documents.
Moreover, in addition to the above, the legislative intent, as expressed in the Conference Report, clearly reflects the view that in camera reviews were to' be a “secondary tool of FOIA enforcement.” Ingle v. Department of Justice, 698 F.2d 259, 264 (6th Cir.1983). The Conference Report notes:
[t]he court may examine records in camera in making its determination under any of the nine categories of exemptions under section 552(b) of the law ... While in camera examinations need not be automatic, in many situations it will plainly be necessary and appropriate. Before the court orders in camera inspection, the Government should be given the opportunity to establish by means of testimony or detailed affidavits that the documents are clearly exempt from disclosure.
S.Rep. No. 1200, 93d Cong., 2d Sess. 9 (1974), reprinted in [1974] U.S.Code Cong. & Admin.News, pp. 6267, 6287-88. Furthermore, the House Report indicates that the FOIA merely “permit[s] such in camera inspection at the discretion of the Court.” H.R.Rep. No. 93-1380, Conference Rep. 93d Cong., 2d Sess. 9 (1974).
*21The Supreme Court has noted that:
The in camera review provision [of the FOIA] is discretionary by its terms, and is designed to be invoked when the issue before the District Court could not be otherwise resolved; it thus does not mandate that the documents be individually examined in every case.
NLRB v. Robbins Tire & Rubber Co., 437 U.S. 214, 224, 98 S.Ct. 2311, 2318, 57 L.Ed.2d 159 (1978). In addition, previous, cases in this Circuit have held that in camera inspections are conducted at the discretion of the trial judge. In Allen v. Central Intelligence Agency, 636 F.2d 1287 (D.C. Cir.1980), this Court undertook a comprehensive review of the legislative history of the 1974 and 1976 Amendments to the FOIA as it related to the issue of in camera inspection. We concluded that:
[t]he Conference Committee ... reported out a bill that, just as the Senate and House versions had, granted reviewing courts broad discretion to employ in camera inspection.
Id. at 1296.7 We have consistently held that with respect to decisions to review documents in FOIA cases, the district courts have substantial discretion. In Ray v. Turner, 587 F.2d 1187, 1195 (D.C.Cir. 1978), this Circuit noted:
Congress left the matter of in camera inspection to the discretion of the district court, without any indication of the extent of its proper use. The ultimate criterion is simply this: Whether the district judge believes that in camera inspection is needed in order to make a responsible de novo determination on the claims of exemption.
See also Hayden v. National Security Agency, 608 F.2d 1381, 1384 (D.C.Cir.1979), cert. denied, 446 U.S. 937, 100 S.Ct. 2156, 64 L.Ed.2d 790 (1980). Given the discretion that Congress invested in the district courts in this matter, and the absence of any indication that in camera inspection was to be required in any given set of circumstances, we decline to adopt the per se rule suggested by appellant in this case.
Appellant has raised several policy arguments in favor of the adoption of such a rule. Specifically, the Center argues that Exemption 5 cases pose unique problems of determining whether segregable factual portions exist within a document, and that without in camera review, a district court is unable to test the accuracy of agency affidavits. Indeed, we have recognized that the issue of “segregability is completely dependent on the actual content of the documents____” Mead Data Central, Inc. v. Department of the Air Force, 566 F.2d 242, 260 (D.C.Cir.1977). For just such a reason, in reviewing a trial court’s exercise of its discretion, we look to such factors as evidence of bad faith and the detail used in the Vaughn Index and affidavit to describe the contents of the documents. See e.g., Allen v. CIA, 636 F.2d 1287, 1298 (D.C.Cir. 1980). While persuasive policy arguments concerning checking the accuracy of agency affidavits may exist in this case, there remains the fundamental principle of saving judicial resources. The “segregability” requirement applies to all documents and all exemptions in the FOIA. If this Court were to adopt the per se rule suggested by appellant, we would be hard pressed not to extend the rule in future cases to the other exemptions. This result would be contrary to the intent of Congress. As we noted in Weissman v. CIA, 565 F.2d 692, 697 (D.C. Cir.1977) (footnotes omitted):
In every FOIA case, there exists the possibility that Government affidavits claiming exemptions will be untruthful. Likewise, in every FOIA case it is possible that some bits of non-exempt material may be found among exempt material even after a thorough agency evaluation. *22If, as appellant argues these possibilities are enough automatically to trigger an in camera investigation, one will be required in every FOIA case. This is clearly not what Congress intended, nor what this Court has found to be necessary.
Even in the face of persuasive policy reasons to adopt a per se rule, as the Supreme Court recently recognized, “it is not our job to apply laws that have not yet been written.” Sony Corp. of America v. Universal City Studios, Inc., — U.S. -, -, 104 S.Ct. 774, 796, 78 L.Ed.2d 574 (1984). In all FOIA cases, it is extremely difficult for any judge to have the necessary expertise to determine the propriety of the claimed exemptions. Such analysis requires conscientious judges and tremendous time and effort. However, until Congress acts to remove the clear grant of discretion expressed in the FOIA, or to relieve the tremendous burden on the trial judge, we are bound to interpret the law as written.
There Was No Abuse op Discretion by the District Judge in this Case
Given our conclusion that the decision on whether to grant a request for in camera inspection is within the discretion of the district court judge, our task is to determine whether the trial judge in this case abused that discretion. The Court below found that in camera review was not required “due to the detailed explanatory material promptly supplied by the EPA.” J.A. 3. On the basis of a detailed affidavit submitted by Charles N. Freed and a detailed Vaughn Index, the Court granted summary judgment against the Center. We find that the trial judge acted properly in this case.
Congress did not mandate in camera inspection for any particular subset of FOIA cases — but “it has nevertheless made clear — by the concern reflected in the 1974 and 1976 Amendments for a thorough and meaningful de novo review — that in' certain cases, such inspection ‘will plainly be necessary and appropriate.’ ” Allen v. Central Intelligence Agency, 636 F.2d 1287, 1297 (D.C.Cir.1980); H.R.Rep. No. 93-1380, 93d Cong., 2d Sess. 8, reprinted in [1974] U.S. Code Cong. & Admin.News at 6267. This Court has recognized that Congress “never isolated those instances” in which in camera inspection of requested documents is “plainly necessary.” Allen, 636 F.2d at 1297. For that reason, we have previously outlined some of the considerations that trial courts should take into account in exercising their discretion.
In Hayden v. National Security Agency, 608 F.2d 1381, 1387 (D.C.Cir.1979), cert. denied, 446 U.S. 937, 100 S.Ct. 2156, 64 L.Ed.2d 790 (1980), this Court noted that affidavits would be sufficient to justify summary judgment without in camera inspection, when they meet the following standard:
[T]he affidavits must show, with reasonable specificity, why the documents fall within the exemption. The affidavits will not suffice if the agency’s claims are conclusory, merely reciting statutory standards, or if they are too vague or sweeping. If the affidavits provide specific information sufficient to place the documents within the exemption category, if this information is not contradicted in the record, and if there is no evidence in the record of agency bad faith, then summary judgment is appropriate without in camera review of the documents.
See also Holy Spirit Ass’n for the Unification of World Christianity v. Central Intelligence Agency, 636 F.2d 838, 845 (D.C.Cir.1981), vacated and remanded on other grounds, 455 U.S. 997, 102 S.Ct. 1626, 71 L.Ed.2d 858 (1982); McGehee v. Central Intelligence Agency, 697 F.2d 1095, 1112 (D.C.Cir.1983); Military Audit Project v. Casey, 656 F.2d 724, 738 (D.C. Cir.1981).8
*23This Circuit has repeatedly held that “when the agency meets its burden [under the FOIA] by means of affidavits, in camera review is neither necessary nor appropriate.” Weissman v. CIA, 565 F.2d 692, 696-97 (D.C.Cir.1977); see also Ray v. Turner, 587 F.2d at 1195. In Brinton v. Department of State, 636 F.2d 600 (D.C.Cir.1980), cert. denied, 452 U.S. 905, 101 S.Ct. 3030, 69 L.Ed.2d 405 (1981), this court reviewed a district court decision granting summary judgment to the State Department without acceding to Brinton’s request for an in camera inspection. The District Court had found the State Department’s affidavits to be sufficiently clear and detailed to establish the applicability of Exemption 5. The Court also found no allegations or evidence of agency bad faith. See Brinton v. Department of State, 476 F.Supp. 535, 538-43 (D.D.C.1979). This Court held:
Because the Department affidavits made a detailed showing of the applicability of the deliberative process ground of Exemption 5, and since there is no contradictory evidence or evidence of Department bad faith, the district court was entirely correct in granting summary judgment without conducting an in camera inspection of the documents.
Brinton, 636 F.2d at 606; see also Church of Scientology of California v. Department of Defense, 611 F.2d 738, 742 (9th Cir.1979) (“If the agency supplies a reasonably detailed affidavit describing the document and facts sufficient to establish an exemption, then the district court need look no further in determining whether an exemption applies.”).
Even the appellant admits that in this case “EPA filed detailed affidavits justifying the withholding, which, on their face, were logical and uncontradicted by anything else in the record.” Brief of Plaintiff-Appellant at p. 21. Additionally, appellant admits that at the time the district court made its determination on the need for in camera review, “there was no evidence of agency bad faith.” Id. Our review of the EPA affidavit and the Vaughn Index convinces us likewise. “Reasonably specificity in affidavits connotes a quality of reliability.” Ray v. Turner, 587 F.2d 1187, 1195 (D.C.Cir.1978). The EPA submissions to the trial court were sufficiently detailed and specific enough to withstand scrutiny. In addition to non-conclusory descriptions of documents in the Vaughn Index, the 23 page affidavit of Charles N. Freed provides a good summary description of the documents in general terms and the grounds for claiming exemptions. Indeed, the affidavit even describes what factual materials were withheld and why they could not be segregated. See Freed Affidavit at 11 26. Appellant relies principally on the case Ash Grove Cement Co. v. FTC, 511 F.2d 815 (D.C.Cir.1975). In that case, this Court held that the trial judge should inspect a random sample of the disputed documents because the initial decision had been based on “inadequate information” and “general descriptions” of the documents. Id. at 816, 817. The Court concluded that “in the absence of more specific document analysis by the agency, such a procedure was necessary to meet the requirement of Vaughn v. Rosen, 484 F.2d 820 (D.C.Cir.1973), cert. denied, 415 U.S. 977 [94 S.Ct. 1564, 39 L.Ed.2d 873] (1974) that judicial determinations under the FOIA be based upon a detailed record.” Id. at 817. Similarly, in Allen v. CIA, 636 F.2d 1287 (D.C.Cir.1980), we noted that one reason for ordering the trial judge to inspect documents was that “[t]he affidavits afford[ed] no basis for a conclusion that all reasonably segregable nonexempt portions of the document have been released” and did not even contain an assertion to that effect. Id. at 1294; see also Holy Spirit, 636 F.2d at 845 (in camera review needed *24when descriptions of the documents were primarily conclusory and often repeat the terms of the FOIA).
In contrast to those cases, we find the affidavit and Vaughn Index in this case to be non-conclusory and specific in their descriptions of the disputed documents. In the absence of agency bad faith at the time of the district court’s decision,9 and given the specificity of the EPA submissions and the absence of any other distinctive factor suggesting a need for in camera inspection in the present case,10 the trial court did not abuse its discretion by refusing to proceed in that fashion.
Appellant claims that the legislative history of the FOIA indicates that the reliance on affidavits without in camera review was intended to be primarily utilized in the particularly sensitive area of national security matters covered by Exemption 1. Brief of Plaintiff-Appellant at p. 18. We do not agree. While preserving the confidentiality of national security documents was undoubtedly and understandably uppermost in the Congress’ mind, there is no indication in the legislative history that the discretion given to the trial judge on the issue of in camera inspection was meant to be used solely, or even primarily, with regard to such documents. In fact, this Court has already noted that the Allen/Hayden standards for reviewing trial court discretion (developed in Exemption 1 cases) should be applied in Exemption 5 cases as well. In Paisley v. CIA, 712 F.2d *25686 (D.C.Cir.1983), both exemptions 1 and 5 were at issue. The Court noted:
If the Government’s affidavits fail to meet the standards of specificity set forth by this Court, see Hayden v. Nat’l Security Agency, 608 F.2d 1381, 1387 (D.C.Cir.1979), cert. denied, 446 U.S. 937, [100 S.Ct. 2156, 64 L.Ed.2d 790] (1980) ... then the District Court should consider in camera inspection of the documents. See ... Holy Spirit Ass’n for Unification of World Christianity v. CIA ...; Allen v. CIA ... (considerations supporting in camera inspection).
Paisley, 712 F.2d at 700 n. 62. The trial judge in this case applied the appropriate standard in reaching his decision.
Conclusion
The decision on whether to conduct in camera inspection of documents in FOIA eases is one addressed to the broad discretion of the trial judge. Upon review of the record in this case, we conclude that there was no abuse of that discretion, and that summary judgment in favor of the Appel-lee was appropriate on the facts of this case.
Affirmed.