| Code | Explanation | From | Through |
|---|---|---|---|
| 1 | Confidential. Executive Order 12958 | 01/01/1970 | 08/31/2018 |
| 2 | Secret. Executive Order 12958 | 01/01/1970 | 08/31/2018 |
| 3 | Top Secret. Executive Order 12958 | 01/01/1970 | 08/31/2018 |
| 4 | Sensitive Compartmented Information. Director of Central Intelligence Directive 1/14 | 01/01/1970 | 08/31/2018 |
| 5 | Q Sensitive. Atomic Energy Act of 1954 | 01/01/1970 | 09/30/2018 |
| 6 | Q Nonsensitive. Atomic Energy Act of 1954 | 01/01/1970 | 08/31/2018 |