All agency records must be made available to the public under FOIA, except:

1. Records properly classified as secret in the interest of national defense or foreign policy.
2. Records related solely to internal personnel rules and practices.
3. Records specifically made confidential by other statutes.
4. Trade secrets and commercial or financial information that is obtained from a person and is privileged or confidential.
5. Inter-agency or intra-agency memoranda or letters, except under certain circumstances.
6. Personnel and medical files and similar files, the disclosure of which would constitute a clearly unwarranted invasion of personal privacy.
7. Records or information compiled for law enforcement purposes, the release of which (a) could reasonably be expected to interfere with enforcement proceedings, (b) would deprive a person of a right to a fair trail or impartial adjudication, (c) could reasonably be expected to constitute an unwarranted invasion of personal privacy, (d) could reasonably be expected to disclose the identity of a confidential source, (e) would disclose investigative techniques, and/or (f) could reasonably be expected to endanger the life or physical safety of any individual.
8. Information contained in or related to certain examination, operating, or condition reports concerning financial institutions.
9. Certain information concerning gas or oil wells.

For a detailed discussion on how these FOIA exemptions have been interpreted and defined by the courts, see the “Justice Department Guide to the Freedom of Information Act.”

To get an idea how the exemptions are used by a particular agency, see that agency’s annual FOIA report, where it tallies it use of each exemption during that year. (The DOJ keeps all departments’ and agencies’ annual reports on its Web site.)