The balloons that exploded in Yerevan at the election meeting of the ruling Republican Party of Armenia on May 4, may have been filled with either hydrogen or methane, since only these gases possess the lift and explosion capacity, deputy director of Geliymash NGO Vladimir Fedotov told Russian RIA Novosti news agency.

“Most likely, it was hydrogen. Helium is absolutely inert, it does not form any chemical reactions,” Fedotov said commenting on allegations that balloons were filled with helium.

“Chemical compounds of helium require very specific conditions, and they are unstable. Respiratory blends, including those for deep-water equipment, are made with helium and hydrogen compounds namely because helium is an inert gas,” the expert said.

When asked whether the balloons may have carried mixture of helium and natural gas, Fedotov said this was not possible. “Helium is extracted from natural gas through liquation, the temperature being such that all other gases remain solid, and only helium is liquid. Therefore, technological reasons rule out any mixture or hydrocarbon remainder in helium,” he stated.

According to him, the balloons hardly had any mixture of helium with other gases; such blend would require special equipment.

“Besides hydrogen, the only version could be methane, though its lift capacity is poor. Still, methane could have exploded. Propane-butane used for household gas stoves is heavier than air, it goes down, while methane, CH4, weighs less than air. Theoretically, the balloons may have been filled with methane,” Fedotov said.

“There is no other inflammable gas which would have a lift capacity; this was either methane or hydrogen,” the expert emphasized.

According to May 5 morning data of the Armenian Healthcare Ministry, 94 of the total 154 people taken to hospitals still undergo medical treatment, including 25 in intensive care units.