The emergency was the second fire in two weeks to break out at the Mina al-Ahmadi complex.
The fire did not disrupt production and was extinguished by fire fighting units from Kuwait Fire Service Directorate, KNPC, Kuwait Oil Company (KOC) and Petrochemical Industries Company,
Speaking to KUNA, a news agency that functions as a branch of Kuwaits Information Ministry, KNPC spokesman Khaled al-Asousi said his organisation will form an investigation team to look at the cause of fire.
The previous fire at the refinery broke out in the complexs waste treatment facility and hospitalised several workers.
In April, engineering, procurement and construction (EPC) contracts were issued for $12bn-worth of contracts on the Clean Fuels Project to expand and upgrade the Mina al-Ahmadi and Mina Abdullah refineries.