The sites struck on Saturday were described by Lt. Gen. Kenneth F. McKenzie, who leads the Joint Staff at the Pentagon, as “fundamental components of the regime’s chemical weapons warfare infrastructure.” They may have been in the past, but it is unclear they were still in active use when American, French and British forces leveled them.

‘Mission Accomplished!’ But What Is the Mission in Syria? APRIL 14, 2018
So far, officials say, two factors make them wonder whether the facilities were still central to Syria’s program. At this point, there are no known casualties at the sites, which suggests that either no one was there during the evening, or they had been previously abandoned. And there are no reports of chemical agent leakage from the sites, despite attacks by more than 100 sea- and air-launched missiles.

Whether those particular sites were still in use or not, the conflict in Syria has demonstrated a larger truth: While it is easy to blow up Mr. Assad’s chemical facilities, it is also relatively simple for him to reconstitute them elsewhere, or just turn to a commercially available substance like chlorine to make a crude poison that any nation is allowed to possess.