Authorities are investigating a chemical explosion at a mobile phone parts manufacturer that left one dead and three injured Monday in central South Korea.

Police said Tuesday they were launching a joint probe with National Forensic Service, Korea National Fire Agency and Korea Energy Agency to identify the cause of the explosion and details surrounding the accident, such as whether safety regulations had been followed.

The explosion occurred at around 2:30 p.m. at a factory for manufacturing phone displays in Jecheon, North Chungcheong Province. It took 48 firefighters and 22 firetrucks about 20 minutes to contain the blaze.

A 38-year-old researcher was killed and three others in the production line suffered second- to third-degree burns, the police said. The three injured victims were transferred to Seoul for treatment at Hangang Sacred Heart Hospital in Yeongdeungpo-gu.

The fire service believes the explosion took place on the first floor of the factory during a test run of newly installed equipment. Damage is estimated to be worth around 20 million won ($16,900), they added.

An autopsy will be conducted to determine the exact cause of the death of the researcher.

By Kim Arin (arin@heraldcorp.com)