LOL! That's a defoliant that hasn't been made in 30 years.
Well, defoliants are so useful in arid deserts.
And since when is phosphorus a chemical weapon, anyway? Then I guess we used chemical weapons in WWII, Korea, and probably Vietnam (don't know about that one, but guessing "yes" from pictures with white flaming objects exploding out.)
Exactly, and why use a defoilant in the desert?