By Pentagon Correspondent Barbara Starr
That explosion last week at a missile plant in Iran appears by all accounts at this point to have been an industrial accident, according to two senior defense officials.
The officials tell CNN that the U.S. believes the Iranians were mixing volatile fuel for a rocket motor for a large ballistic missile when the accident occurred. The officials asked not to be identified because of the sensitive nature of the information.
The explosion also caused other nearby munitons to detonate, killing several Iranian personnel. Iran has been working on long range ballistic missiles that U.S. intelligence believes could be capable of carrying a nuclear warhead if Iran develops one.