This explanation was widely ridiculed, especially in Britain. A good summary is provided in this article on Counterpunch, with the comment by Bellingcat referred to in the article available here. I shall quote the relevant section from the first article in Counterpunch since it provides a good summary
British chemical weapons expert, Col. Hamish de Bretton-Gordon poked holes in Russia’s official account, calling it “fanciful,” noting that blowing up sarin, the alleged gas used in the attack, actually eliminates it. Dan Kaszeta over at Bellingcat, concurred:I am not an expert on the production or storage of chemical weapons. However I recall that in one of her speeches to Goldman Sachs leaked by Wikileaks Hillary Clinton (who as a former US Secretary of State would presumably know) said the following, which does not seem to sit very comfortably with the claims of the British experts cited above
“Even assuming that large quantities of both Sarin precursors were located in the same part of the same warehouse (a practice that seems odd), an air-strike is not going to cause the production of large quantities of Sarin. Dropping a bomb on the binary components does not actually provide the correct mechanism for making the nerve agent. It is an infantile argument. One of the precursors is isopropyl alcohol. It would go up in a ball of flame. A very large one. Which has not been in evidence.”
In Libya we didn’t have that problem. It’s a huge place. The air defenses were not that sophisticated and there wasn’t very—in fact, there were very few civilian casualties. That wouldn’t be the case [in Syria]. And then you add on to it a lot of the air defenses are not only in civilian population centers but near some of their chemical stockpiles. You do not want a missile hitting a chemical stockpile.(bold italics added)
However I was even more interested to read this largely overlooked comment of General H.R. McMaster, President Trump’s National Security Adviser, spoken during his joint press conference with US Secretary of State Rex Tillerson in the immediate aftermath of the Sharyat air base missile strike
Q And on the target, anything else on specifically what you believe was destroyed in the strike?
GENERAL McMASTER: I’ll defer to the Pentagon on that. But there were a number of targets that were associated with the ability of that airfield to operate and to continue mass-murder attacks against the Syrian civilians. And the one thing that I will tell you, though, there was an effort to minimize risk to third-country nationals at that airport — I think you read Russians from that — and we took great pains to try to avoid that.
Of course, in any kind of military operation, there are no guarantees. And then there were also measures put in place to avoid hitting what we believe is a storage of sarin gas there so that that would not be ignited and cause a hazard to civilians or anyone else.(bold italics added)
Maybe I am missing something but it seems to me that General McMaster here is saying that when carrying out the missile strike on Sharyat air base the US took precautions to avoid precisely the sort of scenario which the Russians say actually happened following the Syrian air strike on Khan Sheikhoun, but which Colonel Hamish de Bretton-Gordon says is “fanciful”.
I appreciate that the Bellingcat comment quoted above refers to the manufacturing process for sarin gas, and I have no reason to doubt that “dropping a bomb on the binary components does not actually provide the correct mechanism for making the nerve agent”. However the Russian report quite clearly refers to the manufacturing and storage of chemical weapons at the bombed warehouse, and it is of course precisely the “hazard to civilians” caused by “hitting what we believe is a storage of sarin gas” that General McMaster said the US sought to avoid.
The Bellingcat article makes further claims about the Jihadis’ supposed lack of capacity to produce sarin gas and the supposed inability of both the Jihadis and of the Syrian military to produce sarin gas with a long shelf life. However UN investigators have previously said that Jihadi groups have used sarin gas during the Syrian war, and the technical premises of the Bellingcat claims in relation to Jihadi production of sarin gas have also been comprehensively challenged by this detailed discussion in the Who Attacked Ghouta site, which not only suggests how the Jihadis might produce sarin gas but which shows how they might do so at a reasonable cost.
If it was only Hillary Clinton who was saying that an attack on a chemical storage facility might pose a “hazard to civilians” then at a pinch I would be prepared to accept that as a civilian she might be wrong.
However I refuse to accept that this is so of General McMaster. As a military officer with the resources of the US National Security Council behind him he surely knows what he is talking about.
Frankly, in light of what General McMaster said about the Sharyat air base attack, the Russian version of the Khan Sheikhoun attack does not seem to me “fanciful” at all.