The United Workers Petroleum Industry was formed on the 10th of January 1961. In the early days, UWPI started of with refineries like Shell, ESSO, BP, Caltex, SRC, Castrol, SPC and Mobil to form the union.

After more than 20 years, Shell moved out to form a house union in 1985. SRC and Mobil follow suit. In February 2001, BP, Caltex SPC, Castrol, VOPAK, Cafhi, CHIPS, SOPS and Infineum merged with SPCEU

SPCEU consisted of PCS, TPC, CPSC, CPCA, KCS, EGS, DSPL, EMPL, FM and Seraya. ESSO formed a house union with Mobil after Exxon merge with Mobil. This house union was known as EMSEU. Following that, BP bought over Castrol. Seraya Chemicals became 100% Shell owned

SPCEU merged with UWPI and Seraya transferred to SSEU, We organized Mitsui Phenol, Mitsui Bisphenol, COIM, Syngas and Mitsui Elastomers. We organize Chevron Oronite as "Managed General Branch". We organize Oiltanking Terminal and Oiltanking Odfjell. We also organize DIC Alkylphenol Singapore Pte Ltd in 2006. We organized Helios Terminal. Nexsol changed their name to STEPAN, Helios Terminal merged with Oiltanking. We continue to unionize JAC, Ecolab, Evonik and Prime Evolue. UWPI now has 33 Branches.