VKA was a plant hormone, 2,4-D (full name, 2,4-Dichlorophenoxyacetic acid), one of the components of a mixture that some years later came to be called Agent Orange. … Norman treated test plots with VKA mixed with diesel fuel, tributyl phosphate, and other substances, and worked out how best to deliver it to rice, wheat, and other staple crops from B-25 bombers fitted with 550-gallon tanks.

Nicholson Baker, Baseless- My Search for Sec…, loc. 324