Photo: Mesquite, central Texas. © 2017 Delena Norris-Tull
2,4-D and 2,4,5-T, post-World War II
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, October 2020.
Agent Blue, Agent Green, Agent Pink, Agent Purple, Agent White, Agent Purple, and Agent Orange were known as the Rainbow Herbicides. 2,4-D was one of the ingredients in Agent Orange and most of the other Rainbow Herbicides, defoliants used to kill the leaves of trees and to destroy crops during the Vietnam War. However, 2,4-D was not the cause of the serious health effects caused by Agent Orange and other herbicides in this group. Side effects from contaminants in some of these herbicides have resulted in long-term health affects for American soldiers. In particular, the contaminant in the 2,4,5-T component of Agent Orange that has caused so many health problems is TCDD, a highly toxic dioxin, a chemical that is linked to various cancers.
The Rainbow Herbicides were all used in the Vietnam War from 1961-1971, to defoliate trees to prevent the North Vietnamese from hiding in the forests. And some were used to defoliate rice fields, in attempts to starve the North Vietnamese. They were also used in wars in Cambodia and Laos. Most of these herbicides combine 2,4-D with 2,4,5-T. The damage to the Vietnamese forests and agriculture was massive, and resulted in a buildup of dioxins, that has impacted the health of millions of people.
Some of these herbicides were also used in the U.S. in the 1940s-1960s to defoliate trees, to convert forested areas to agriculture. Other countries also used these herbicides.
Stellman, et al., 2003, reevaluated military data, previously published in 1974 by the US National Academy of Sciences, on the amount of Agent Orange and other defoliant herbicides that were used in Vietnam between 1961-1971. “About 65% of the herbicides contained 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), which was contaminated with varying levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)…. In April 1970, 2,4,5-T was banned from most US domestic uses, on the basis of evidence of its teratogenicity.” Stellman, et al., 2003, calculated that approximately 75,540,954 litres of the eight so-called Rainbow Herbicides were used in Vietnam. When compared with the 1974 report, “The spray inventory is expanded by more than seven million litres, in particular with heavily dioxin-contaminated herbicides…Hamlet census data reveal that millions of Vietnamese were likely to have been sprayed upon directly.” Stellman, et al., 2003 report that “no large-scale epidemiological study of herbicides and the health of either the Vietnamese population or war veterans has been carried out.”
Jim Pike, formerly with the NRCS Field Office for Laramie County, Wyoming, told me that he served in the Vietnam War, and thought nothing at the time about being drenched in Agent Orange. That early experience with the country’s lack of concern with the potential toxicity of chemicals causes him to be much more aware of the possibility that we are poisoning our environment and ourselves even more, in the current use of herbicides and pesticides to manage weeds and pests.
2,4-D is still one of the most heavily used herbicides today, and is found in over 1500 herbicides. Its toxicity in humans is uncertain. The World Health Organization has listed it as a possible human carcinogen since 1987. But the US EPA has concluded that there is inadequate research to support the assumption that it could be a human carcinogen.
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2,4-D and 2,4,5-T, post-World War II
Summaries of the research and commentary by Dr. Delena Norris-Tull, Professor Emerita of Science Education, University of Montana Western, October 2020.
Agent Blue, Agent Green, Agent Pink, Agent Purple, Agent White, Agent Purple, and Agent Orange were known as the Rainbow Herbicides. 2,4-D was one of the ingredients in Agent Orange and most of the other Rainbow Herbicides, defoliants used to kill the leaves of trees and to destroy crops during the Vietnam War. However, 2,4-D was not the cause of the serious health effects caused by Agent Orange and other herbicides in this group. Side effects from contaminants in some of these herbicides have resulted in long-term health affects for American soldiers. In particular, the contaminant in the 2,4,5-T component of Agent Orange that has caused so many health problems is TCDD, a highly toxic dioxin, a chemical that is linked to various cancers.
The Rainbow Herbicides were all used in the Vietnam War from 1961-1971, to defoliate trees to prevent the North Vietnamese from hiding in the forests. And some were used to defoliate rice fields, in attempts to starve the North Vietnamese. They were also used in wars in Cambodia and Laos. Most of these herbicides combine 2,4-D with 2,4,5-T. The damage to the Vietnamese forests and agriculture was massive, and resulted in a buildup of dioxins, that has impacted the health of millions of people.
Some of these herbicides were also used in the U.S. in the 1940s-1960s to defoliate trees, to convert forested areas to agriculture. Other countries also used these herbicides.
Stellman, et al., 2003, reevaluated military data, previously published in 1974 by the US National Academy of Sciences, on the amount of Agent Orange and other defoliant herbicides that were used in Vietnam between 1961-1971. “About 65% of the herbicides contained 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), which was contaminated with varying levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)…. In April 1970, 2,4,5-T was banned from most US domestic uses, on the basis of evidence of its teratogenicity.” Stellman, et al., 2003, calculated that approximately 75,540,954 litres of the eight so-called Rainbow Herbicides were used in Vietnam. When compared with the 1974 report, “The spray inventory is expanded by more than seven million litres, in particular with heavily dioxin-contaminated herbicides…Hamlet census data reveal that millions of Vietnamese were likely to have been sprayed upon directly.” Stellman, et al., 2003 report that “no large-scale epidemiological study of herbicides and the health of either the Vietnamese population or war veterans has been carried out.”
Jim Pike, formerly with the NRCS Field Office for Laramie County, Wyoming, told me that he served in the Vietnam War, and thought nothing at the time about being drenched in Agent Orange. That early experience with the country’s lack of concern with the potential toxicity of chemicals causes him to be much more aware of the possibility that we are poisoning our environment and ourselves even more, in the current use of herbicides and pesticides to manage weeds and pests.
2,4-D is still one of the most heavily used herbicides today, and is found in over 1500 herbicides. Its toxicity in humans is uncertain. The World Health Organization has listed it as a possible human carcinogen since 1987. But the US EPA has concluded that there is inadequate research to support the assumption that it could be a human carcinogen.
Reference:
- Stellman, J.M., Stellman, S.D., Christian, R., Weber, T., & Tomasallo, C. (April 17, 2003). The extent and patterns of usage of Agent Orange and other herbicides in Vietnam. Nature, 422(6933):681-687.
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