The July 26 explosion in Aleppo, northern Syria, was reported at the time. The official Sana news agency said 15 Syrian military personnel were killed and 50 people were injured, most of them slightly from flying glass.
The agency said only that “very explosive products” blew up after fire broke out at the facility and that the blaze was not an act of sabotage.
But in the September 26 edition of Jane’s Defence Weekly, Syrian defence sources were quoted as saying the explosion happened during tests to weaponise a Scud C missile with mustard gas, which is banned under international law.
Fuel caught fire in a missile production laboratory and “dispersed chemical agents (including VX and Sarin nerve agents and mustard blister agent) across the storage facility and outside.
“Other Iranian engineers were seriously injured with chemical burns to exposed body parts not protected by safety overalls,” the publication quoted the sources as saying.
Among the dead were “dozens” of Iranian missile weaponisation engineers, it added.
The claims come as North Korea denied reports it was helping Syria develop nuclear weapons and intense speculation that a recent Israeli air raid on Syria may have targeted a joint nuclear project.
Jane’s said the regime in Damascus has since imposed a media black-out on the blast and had “destroyed” evidence that base was being used as a missile production site with Iranian help.
It also questioned the government’s claim that the explosion occurred because of a sudden rise in the ambient air temperature that caused a chemical reaction of sensitive and highly volatile substances.
One of its sources described the explanation as “implausible” because the blast happened at about 4:30 am, two hours before sunrise when temperatures were cool.
The article also quoted Syrian opposition sources as noting that vehicles destined for car bomb attacks in Iraq are prepared at the same facility under the supervision of Syrian intelligence and the Iranian Revolutionary Guards.
Jane’s assessed that the incident confirmed information that the two countries have been involved in developing chemical weapons for more than two years under a strategic co-operation agreement.
It said Iran helped Syria in the planning, establishment and management of five facilities designed to develop chemical weapons on an industrial scale.
An Iranian chemical manufacturer, whose identity Jane’s said it knows and with connections to the Islamic republic’s defence industry, and a Syrian firm with links to the military have made a number of deals since 2004.
One of Jane’s sources said they involved the importation of “hundreds of tonnes of sodium sulphide, hydrochloric acid and ethylene glycol-MEG from Iran” which can be used to produce mustard gas and Sarin.
