| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| BULGARIA | Adherence | 21/08/1972 | |
| CANADA | Signature | 26/06/1956 | |
| CANADA | Ratification | 27/03/1957 | |
| CUBA | Adherence | 28/11/1975 | |
| DENMARK | Signature | 09/07/1956 | |
| DENMARK | Ratification | 23/11/1956 | |
| FRANCE | Signature | 09/07/1956 | |
| FRANCE | Ratification | 10/01/1959 | |
| GERMAN DEMOCRATIC REPUBLIC | Adherence | 21/05/1974 | |
| GERMANY FEDERAL REPUBLIC | Accession | 27/06/1957 | |
| ICELAND | Signature | 09/07/1956 | |
| ICELAND | Ratification | 23/11/1956 | |
| ITALY | Signature | 28/06/1956 | |
| ITALY | Ratification | 07/06/1957 | |
| JAPAN | Accession | 01/07/1970 | |
| Land Berlin | Accession | 26/08/1957 | |
| NORWAY | Signature | 03/07/1956 | |
| NORWAY | Ratification | 15/05/1957 | |
| POLAND | Accession | 25/07/1963 | |
| PORTUGAL | Signature | 03/07/1956 | |
| PORTUGAL | Ratification | 17/01/1957 | |
| ROMANIA | Accession | 21/03/1967 | |
| SOVIET UNION | Accession | 11/08/1958 | |
| SPAIN | Signature | 05/07/1956 | |
| SPAIN | Ratification | 02/05/1957 | |
| UNITED KINGDOM | Signature | 29/06/1956 | |
| UNITED KINGDOM | Ratification | 02/04/1957 | |
| UNITED STATES OF AMERICA | Signature | 09/07/1956 | |
| UNITED STATES OF AMERICA | Ratification | 22/05/1957 | |
| UNITED STATES OF AMERICA | Withdrawal | 31/12/1976 |