During World War II, the Empire of Japan occupied the city in 1942, as part of the occupation of Indonesia, and it was bombed by the Allies in first Balikpapan Battle in 1942 and second battle in 1945. The battles impacted critical infrastructure, including the oil refinery stations and seaport which were completely burned to the ground. Upon Indonesia's independence, BPM extended its activities in Balikpapan until 1965 when Pertamina, the Indonesian state-owned oil company, took control over the ownership of BPM and its oil exploration activities.