Cosmo in Japan traces its corporate roots to
Maruzen Petroleum (丸善石油株式会社), a company established in 1931, although the oil business operated by Maruzen was originally established by Zenzo Matsumura in
Kobe in 1907. Cosmo Oil Company was formed on April 1, 1986, through the merger of Maruzen Petroleum and Daikyo Petroleum, a group of oil businesses based in
Niigata Prefecture, which merged in 1939. A major fire occurred at the Cosmo refinery in Ichihara, as a result of the
2011 Tōhoku earthquake. It was extinguished after ten days, injuring six people and destroying storage tanks The ultimate cause was traced to the collapse of supports for
LPG Tank 364, which had been filled with water and undergoing hydrostatic testing at the time the earthquake struck. The collapse fractured LPG pipes, releasing gas that then ignited, in turn igniting LPG in several adjacent tanks. In February 2015, the company said it will reorganize itself under a holding company to boost profitability. Along Cosmo, the other three shareholding companies are
Showa Shell Sekiyu, TonenGeneral Sekiyu, and
Sumitomo Corporation, all with 25% of the ownership. ==Refineries==