AEOI spokesman Behrouz Kamalvandi said the Thursday accident had no casualties and did not disrupt running operations at the facility.
He said there is no cause for concern over possible contamination as the warehouse was not operational.
He said expert teams are now on the ground to look into the causes of the accident.
Later in the day, Natanz governor said it was a fire, but “there is no need for concern from any aspect”.
No further details are available at this point.