A fire broke out on Sunday night at a wastewater storage unit of PTT Global Chemical Plc (PTTGC) in Map Ta Phut, Rayong.
PTTGC is the petrochemical arm of national oil and gas conglomerate PTT Plc.
One worker was reported injured, but not seriously. The fire at the phenol production facility was extinguished within two hours, according to a company statement.
The facility has a full production capacity of 250,000 tonnes of phenol a year, and the fire is unlikely to disrupt operations. Phenol is an aromatic organic compound primarily used to synthesise plastics and related materials.
The company said the emergency status was lifted after the fire was put out early yesterday morning. Officials are assessing the damage.
PTTGC has invested 10 billion baht to double the capacity of the plant since 2014.
Thailand's largest maker of petrochemicals is upbeat about earnings from its newly expanded facilities in Thailand and France.
The expansion will help increase capacity by 7% from the current 8.8 million tonnes a year.