"Gas leakage from a pipeline that linked the gas network from the provincial capital Ahvaz to Mahshahr city near the Persian Gulf caused the blast," IRNA quoted Jamal Alami as saying.
The fatal explosion destroyed a bus, a truck and two private cars passing near the explosion site.
“The bus had no passengers but the driver was wounded,” he added.
Aging infrastructure that caused the rupture in the pipeline has been blamed for the blast.
It has been reported that a one-meter pipe was disconnected (due to decay) from the main pipeline 150 meters from a nearby road, 15 kilometers from Mahshahr. Leaked gas blew across the road and passing cars caused sparks and the eventual explosion.
Official National Iranian Gas Company data show that close to 37,000 kilometers of high-pressure gas pipes are in use in different parts of the country. Some pipes were laid decades ago and leakage and other unforeseen incidents can happen anytime if safety measures are not enforced on time.
Almost 27,000 villages, constituting 82% of the rural population and 97% of the urban population are connected to the national grid.
According to NIGC data, more than 22 million households in 1,106 cities and 24,260 towns are linked to the rapidly expanding piped-gas system.