Though the fire was extinguished by fire service personnel in around half-an-hour but services remained disrupted for some time. No case of injury was reported, airport sources said.
However, smoke entered the Area Control Tower, located on the third floor, through air-conditioning ducts and nearly 40 employees had to be evacuated as a result.
Four international flights were diverted to Bangalore and Hyderabad before normality was restored at the Chennai airport around 7.30 am, sources said.
Airports Authority of India sources said the batteries which burst were part if the Advanced Surface Movement and Guidance Control System (ASMGCS) kept in the third floor of the ATC tower. The ASMGCS was disrupted after they burst. The lighting system at the tower was partially restored at 3 am.
It was learnt that similar incidents had occurred in Mumbai and New Delhi airports in the past. In 2007, batteries of uninterrupted power supply system caught fire in Mumbai while a similar incident took place in New Delhi a few months ago. Operation officials said that batteries of uninterrupted power supply system should be housed separately and with proper ventilation facilities to avoid such incidents.