About Us


1940 Nihon Tennen Gas Kogyo Co., Ltd. was established in Yotsuya, Shinjuku-ku, Tokyo with a plant in Shirako, Chosei-gun, Chiba. Started production of natural gas and glass using the natural gas.
1944 Acquired Nihon Kansui and started manufacturing iodine, bromine, salt, etc.
1954 Started production of potassium iodide.
1957 Concluded a friendship agreement concerning natural gas supply with Toyo Koatsu Kogyo Co., Ltd. (currently Mitsui Chemicals, Inc.).
1961 Started supplying household gas to Shirako Municipal Gas (currently Shirako Municipal Gas Office).
1962 Established iodine production technology using ion exchange resin through joint research with Nippon Organo Shokai Co., Ltd. (currently Organo Corporation).
1963 Completed Koji plant.
1966 Changed iodine production from activated carbon technology to ion exchange resin technology.
1969 Established new iodine adsorption plant in Yokoshiba-machi, Chiba.
1974 Obtained capital participation from Tomen Corporation. (currently Toyota Tsusho Corporation).
1978 Completed development of Hanuki area (1 plant, 10 wells).
1989 Completed development of Kobayashi area (1 plant, 8 wells).
1993 Completed automation of mining facility and iodine production facility.
1995 Obtained capital participation from Kanto Natural Gas Development Co., Ltd.
1996 Obtained ISO9002 certification for the production of iodine and potassium iodide.
Changed the company name to Nihon Tennen Gas Co., Ltd.
2003 Obtained ISO9001 certification for the production of iodine and potassium iodide.
2006 Acquired Kujukuri plant from Kanto Natural Gas Development Co., Ltd.
2007 Became a consolidated subsidiary of Kanto Natural Gas Development Co., Ltd.
2010 Completed new blowing-out tower for iodine production in Chiba plant.
2011 Supplied potassium iodide for stable iodine tablets as the only manufacturer in Japan during the nuclear emergency caused by the Great East Japan Earthquake.
2014 Became a group company of K&O Energy Group Inc.
2015 Completed new office building in Shirako-machi.
Completed first phase of development in the Kayaba area (1 plant, 5 wells).
2016 Moved head office from Nihonbashi, Chuo-ku, Tokyo to Shirako-machi, Chiba.
2017 Completed the second blowing-out tower in Chiba plant.
2019 Completed blowing-out tower in Kujukuri plant.
2022 Restructured business with Kanto Natural Gas Development Co., Ltd. and changed the company name to K&O Iodine Co., Ltd.