Tehran, Iran (CNN) -- One of the longest oil pipelines in Iran exploded Friday and burned for 10 hours before firefighters were able to extinguish it, Iranian media reported.
Authorities are investigating the cause of the blast in the western town of Qale Naar, Iran's state-run Press TV reported.
Hundreds of firefighters responded at the scene, working through the day to contain the blaze.
"The production of oil in the southern oil fields is still continuing at full capacity and the output of the oil wells is transferred to other pipelines," said Hormoz Ghalavand, executive director of the National Iranian South Oil Company.
Ghalavand said on the national oil company's website that 40 thousand barrels per day pass through the pipeline.
Flames leaped as high as 40 meters (131 feet) and the fire covered an area of 300 square meters (3,229 square feet).
Iran is the world's fourth largest oil producer.
CNN's Mitra Mobasherat and Hamdi Alkhshali contributed to this report.