"Another"

Even after they've been outed for lying about the supposed previous attack, the White House is running with this narrative.

The White House issued an ominous warning to Syrian President Bashar al-Assad on Monday night, pledging that his regime would pay a "heavy price" if it carried out another chemical attack this year.

[...]

"The United States has identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children," [White House press secretary Sean] Spicer said in the statement. "The activities are similar to preparations the regime made before its April 4, 2017 chemical weapons attack.

"As we have previously stated, the United States is in Syria to eliminate the Islamic State of Iraq and Syria," he continued. "If, however, Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price."

  WaPo

That never happened.

And our UN ambassador has already pre-assigned culpability, a nice cover for any false flag operations. A nod to our surrogates in Syria to go ahead with a gas attack.

Surprisingly, and shamefully, this Washington Post article does not mention that the allegation of a first attack has been negated, much less contested.

...but hey, do what you want...you will anyway.