| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| BELGIUM | Accession | 04/05/1956 | |
| DENMARK | Accession | 06/10/1960 | |
| FRANCE | Signature | 26/05/1952 | |
| GERMANY FEDERAL REPUBLIC | Signature | 26/05/1952 | |
| GERMANY FEDERAL REPUBLIC | Ratification | 30/03/1954 | |
| GREECE | Accession | 04/11/1955 | |
| ITALY | Accession | 27/07/1955 | |
| LUXEMBOURG | Accession | 13/05/1958 | |
| NETHERLANDS THE | Accession | 06/09/1955 | |
| NORWAY | Accession | 17/10/1958 | |
| UNITED KINGDOM | Signature | 26/05/1952 | |
| UNITED STATES OF AMERICA | Signature | 26/05/1952 |