ping
Proper application of these chemicals benefits all of us, protecting food supplies and stores from insects and fungi, protecting our hides from blood sucking, disease carrying critters and protecting our arable land from noxious weeds.
I don't condone the aerial spraying of defoliants in VN but only on the point of poor coordination with troop movement or location. Defoliants were used not to "burn" off leaves of trees but to cause them to abcise and fall, denying the enemy cover. This too worked to our benefit.
The only chem agent I know of that was used in VN was Phosgene (tear gas). Other stuff used in munitions was "willie peter" and napalm. Both nasty stuff.