The reason for the ban in the first place.....
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U.S. believes ISIS' bomb-making research includes new generation of explosives
Amid the bombed-out ruins of Mosul University, U.S. officials say they have uncovered evidence that the Islamic State of Iraq and Syria (ISIS) was developing a new type of bomb that could pass through an airport scanner undetected.
CBS News joined Iraqi Special Forces in Mosul just days after the hard-fought battle to recapture the University in January. It's long been believed that Mosul University was the center of the militants' bomb-making projects, using the school's equipment and labs. "
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U.S. believes ISIS' bomb-making research includes new generation of explosives - CBS News