China and Russia may be candidates, but not the only ones, if they have any role at all. Another possibility is that the Soviets left behind white phosphorus in the 1980s. But how much of this stuff was left behind and who exactly took inventory of it? How did it fall into rebel hands after more than two decades? The logistics of how white phosphorus could be in rebel hands now leaves more unanswered questions and it appears as a pretext to deflect attention from possible NATO use. The US government and western media have accused the rebels of using the chemical, and in every instance admitted that NATO uses it but for uses other than warfare, although related to war. This is as close to an admission of use as we will ever get from the US and NATO.
NATO and US have a history of denying atrocities and war crimes that contracted mercenaries and US-paid warlords carry out against civilians. Theft, rape and murder, desecration of mosques and mutilation of corpses are some of the atrocities that US-paid warlords have carried out. The US has backed ethnic Tajik elements against ethnic Pashtun civilians. Although the UN confirmed allegations of war atrocities and US/NATO use of disparate ethnic tribes against one another, NATO denies any wrongdoing.