| 16 August 1957 | | Scheme accepted | 'plans approved by DoGC for site preparation work, estimated cost ₤750,000, at Grangemouth Airfield for new chemical plant to be built by British Hydrocarbon Chemicals, Ltd.' per Builder p303 |
| 22 April 1960 | | Proposed | £5m extension and three new plants which s/b online by 1961 per Builder p808 |
| 16 September 1960 | | Build/construction | tender accepted by George Wimpey & Co. for civil engineering and building works and pipework installation in expansion at British Hydrocarbon Chemicals per Builder p551 |
| 28 January 1966 | | Alterations and additions | Planning permission granted for £2.5m extension to begin mid-1967 |