FOIA contains a number of exemptions that permit agencies to withhold responsive records or portions thereof in response to a request.
Following the codification of the Foreseeable Harm Standard as part of the 2016 FOIA Improvement Act, an agency cannot withhold records simply because they fall within the scope of an exemption. Rather, the agency must also show that it "reasonably foresees that disclosure would harm an interest protected by an exemption" or that disclosure is prohibited by law.
Agencies may invoke more than one exemption at a time. For example, in Poitras v. Dep’t of Homeland Sec., the FBI argued that portions of the filmmakers’ requested information was exempt under Exemptions 5, 7(A), 7(D), and 7(E).  The court analyzed each exemption separately and granted summary judgment for the government. 
List of Exemptions
Visit the following pages to read about FOIA's exemptions in more detail:
- Exemption 1
- Exemption 2
- Exemption 3
- Exemption 4
- Exemption 5
- Exemption 6
- Exemption 7
- Exemption 8
- Exemption 9
Non-responsiveness not a basis for withholding part of a responsive record
The Court of Appeals for the D.C. Circuit has held that the redaction of non-responsive material within records that are otherwise responsive is improper. "[O]nce an agency itself identifies a particular document or collection of material—such as a chain of emails—as a responsive 'record,' the only information the agency may redact from that record is that falling within one of the statutory exemptions."
- 5 U.S.C. § 552(b)
- 5 U.S.C. § 552(a)(8).
- Poitras v. Dep't of Homeland Sec., 303 F. Supp. 3d 136, 151-59 (D.D.C. 2018).
- Id. at 164.
- American Immigration Lawyers Association v. Executive Office for Immigration Review, 830 F.3d 667 (D.C. Cir. 2016), available at http://foiaproject.org/dc_view/?id=3004220-DC-15-5201-appeal-opinion
- American Immigration Lawyers Association v. Executive Office for Immigration Review, 830 F.3d at 678-79