From:
Hong Kong Government Gazette, May 3, 1940
Order.
The premises described in the Schedule to this order are hereby declared to be protected places for the purpose of the Defence Regulations, 1939.
…..
Schedule.
…
B.-Gas Works
I. The Hong Kong and China Gas Company’s works and premises in Hong Kong at-
(1) Whitty Street, between Des Voeux Road West and Queen’s Road West, comprising Marine Lots Nos. 190 and 191;
(2) between Queen’s Road West and Clarence Terrace, Inland Lot No. 834 Section A;
(3) Smithfield, Kennedy Town, Inland Lot No. 4098;
(4) Cross Lane, Wanchai, Inland Lot No. 1251.
II. The Hong Kong and China Gas Company’s works and premises in Kowloon at-
(1) Ma Tau Kok between To Kwa Wan Road and the Harbour, Kowloon Marine Lot No. 102 and also the adjacent pier, Kowloon Permanent Pier No. 70;
(2) Jordan Road bounded by Shanghai Street, Nanking Street and Battery Street, Kowloon Inland Lot No. 395.
Found at http://sunzi.lib.hku.hk/hkgro/view/g1940/581611.pdf
This list gives the exact loacation of gas works in 1940.
It seems that there were two facilities at Shek Tong Tsui: north and south of Queen's Road. Currently, only the one south (Gas Works, Shek Tong Tsui [????-????]) has a marker, the northern one doesn't exist yet. This place can be seen on the 1905 map marked as gas works, also on the map from 1945. On the 1952 map a round structure (gas holder?) is seen north of Queen's Road, and two south. Probably two gas works existed there - at least some years - just like at Ma Tau Kok.