A February 22, 1965 Dow Chemical Corporation internal memorandum provided a summary of a meeting in which 13 executives discussed the potential hazards of dioxin in 2,4,5-T. Following that meeting, Dow officials decided to meet with other makers of the chemical and formulate a stance on Agent Orange and dioxin.
In March 1965, Dow official V.K. Rowe convened a meeting of executives of Monsanto, Hooker Chemical, which operated the Love Canal dump, Diamond Alkali, the forerunner of Diamond-Shamrock, and the Hercules Powder Co., which later became Hercules, Inc.
According to documents uncovered only years later, the purpose of this meeting was "to discuss the toxicological problems caused by the presence of certain highly toxic impurities" in samples of 2,4,5-T. The primary "highly toxic impurity" was 2,3,7,8 TCDD, one of 75 dioxin compounds.
Three months later, Rowe sent a memo to Ross Mulholland, a manager with Dow in Canada, informing him that dioxin "is exceptionally toxic, it has a tremendous potential for producing chloracne (a skin disorder similar to acne) and systemic injury." Rowe ordered Mulholland in a postscript to the letter that "Under no circumstances may this letter be reproduced, shown or sent to anyone outside of Dow." Among those in attendance at one of the meetings of chemical company officials was John Frawley, a toxicologist for Hercules, Inc. In an internal memorandum for Hercules officials, Frawley wrote in 1965 that Dow was concerned the government might learn of a Dow study showing that dioxin caused severe liver damage in rabbits. Dow was concerned, according to Frawley, that "the whole industry will suffer." Frawley said he came away from the meeting with the feeling that "Dow was extremely frightened that this situation might explode" and lead to government restrictions.
The concern over dioxins was kept quiet and largely out of the public view. The U.S. government and the chemical companies presented a united front on the issue of defoliation, claiming it was militarily necessary to deprive the Viet Cong of hiding places and food sources and that it caused no adverse economic or health effects to those who came into contact with the rainbow herbicides, particularly Agent Orange.
