In 1977, an offshore fertilizer project was started on two ships owned by Pertamina, the largest Indonesian oil producer, which later became the beginning of the establishment of PT Pupuk Kalimantan Timur.

The main raw material for the plant in Bontang is natural gas which is piped from Muara Badak, about 60 km from the factory location.

The Kaltim-2 plant was built in early 1982 and completed 3 months ahead of the stipulated schedule and succeeded in achieving commercial operations faster than East Kalimantan.

To support Kaltim-5 operations, Pupuk Kaltim will also build an ammonia plant with a capacity of around 600,000 tons per year.

While NPK fertilizer production is as much as 350,000 tons per year with factories in three cities, namely: Bontang, Semarang and Surabaya.