SET-listed Tata Steel Thailand Plc (TSTH) says an electric arc furnace steel plant in Rayong province is expected to resume full operations within 15 days after its technician team and local government staff complete an investigation.
The plant had an explosion on the morning of Oct 6 when the electric arc furnace was warming after relining.
The facility is run by TSTH's subsidiary -- Siam Construction Steel Co -- in Rayong's Map Ta Phut Industrial Estate.
Sirorote Matemanosak, vice-president for human resources and corporate affairs, said TSTH is looking at the damage assessment procedures and cooperating with the government's local agencies.
The state-run Industrial Estate Authority of Thailand (IEAT) is the operator of the Map Ta Phut location and is taking part in this process.
"TSTH and IEAT expect to conclude the investigation today," Mr Sirorote said.
TSTH submitted a letter to the Stock Exchange of Thailand on Tuesday that there was no leakage of hazardous chemicals to the environment and no impact to neighbouring factories and surrounding communities.
Downstream rolling mill operations are running as normal. Four workers who were present near the furnace at the time of the explosion were injured.
The four injured workers were immediately taken to a hospital. Two had minor injuries and have since been allowed to return home.
The two others had burns and are still being treated at the hospital.
TSTH said it is providing the best possible care to all injured workers.
The plant is working to return to normal operations. Repair of the machine and damaged roof has begun.
An expert team was summoned to review the furnace's safety system, said Mr Sirorote.
TSTH plans to institute necessary safety measures to prevent a recurrence of the accident, he said.
Support from external agencies that can help with safety measures will be used as appropriate.
Review and practice of an emergency response plan shall take place as per the norms of IEAT, said Mr Sirorote.
"We have a risk management process that complies with government policy, so we are confident we can prevent future accidents," he said.
Siam Construction Steel Co produces billet and hot rolls steel into rebar, with a capacity of 500,000 tonnes per year.
Mr Sirorote said the investigation has not affected TSTH's business, as it can supply steel products to dealers and retailers as normal.
Somchint Pilouk, IEAT's governor, said it told TSTH to close the plant for 15 days until the investigation is complete.
The primary cause was found to be a malfunction of the ignition of a natural gas system when the electric arc furnace was warming after relining, she said.
As a result, the accumulation of natural gas in the furnace coincided with the ignition of the fuel system, causing it to catch fire and explode inside the furnace.
Some property was damaged such as a roof and part of the plant's wall, including the electric arc furnace's control room.
"We contacted Siam Construction Steel on Oct 8 regarding the investigation and it reported an asset loss of 4.8 million baht," Ms Somchint said.
She said the IEAT will keep the public up to date on this explosion investigation.
TSTH has been told to provide updated information every five days to the IEAT, Ms Somchint said.