SEOUL - One worker was killed and the other was injured on Monday in South Korea's oil storage tank explosion, according to Yonhap news agency.

The explosion occurred at about 11:15 am local time (0215 GMT) at a factory in Ulsan, some 300 km southeast of the capital Seoul.

One of the two workers in their 30s at the scene was taken to a hospital unconscious to undergo surgery, but died later in the day.

The other suffered a serious injury that was not life-threatening.

The two victims were believed to be caught in the explosion while opening a hatch on top of the tank and checking the amount of petrochemicals inside.

The fire authorities mobilized about 230 firefighters and 44 equipment, including fire trucks, to put out the fire that broke out after the explosion.

There were four to five other tanks containing lubricants, biodiesel and others around the tank where the explosion and fire broke out.

The fire was completely extinguished some three hours later.