Thailand’s second-biggest cement firm, Siam City Cement PCL  said on it had shut one of its three plants after an explosion earlier this week that killed three workers.

"We have to stop operations temporarily for security," said company spokesman Sataporn Phettongkum. A fire had sparked the explosion in the fuel filling system.

The plant accounts for 29 per cent of the company’s total 12.5Mta capacity, but other plants could step up production, he said.  The company was operating at about 70 per cent of total capacity, before the incident happened, Sataporn said.

He declined to give an estimate for the cost of the damage or how long the plant would be shut. Government officials would investigate the damaged factory on Friday, he said.

Siam City Cement, 32 percent owned by Switzerland’s Holcim , had earlier said it had expected minimal impact from the explosion in a fuel filling system at its cement factory in Saraburi province, northeast of Bangkok.