In a TV Q&A session on Saturday, Zanganeh said for the time being cause(s) of the disaster is under investigation just from Saturday morning after extinguishing of the fire.

He said outcome of the verification will be unveiled by the weekend as the conclusion of the study will help prevent repetition of such incidents in the future.

He added that such investigations are helpful in reformulation of methods and improvement of the systems to check any such incidents in the future.

"Undoubtedly a technical reason is behind. Due to leakage of the paraxylene pump in Bou Ali Sina Petrochemical Plant  such an event happened and spread to two more storage tanks."

He said fire in the paraxylene tower was fully contained at 05:00 am and the first reservoir tank on Thursday and the second one at 2 am Saturday.

While thanking all those involved in fire containment, Zanganeh said all involved in the process had did their best to check the disaster.

He said the fire had left no one injured.

Concluding his remarks, Zanganeh said upgrading safety standards and observation of the environmental exigencies is a must. "That's what we learned from the incident."

Zanganeh said the facility will soon resume work.