Operation Ranch Hand
The aerial spraying program ran from 1962 to 1971 over South Vietnam. It dispersed roughly 19 million gallons (about 72,000 m³) of herbicides in total.
Conditions Covered by Exposure Claims
More than a dozen diagnosed conditions — including several cancers, type 2 diabetes, ischemic heart disease and Parkinson's disease — are covered presumptively when a veteran served in Vietnam between 9 January 1962 and 7 May 1975. This guide lists those conditions, traces the 1962–1971 spraying campaign behind them, and explains how presumptive service connection is established.
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The aerial spraying program ran from 1962 to 1971 over South Vietnam. It dispersed roughly 19 million gallons (about 72,000 m³) of herbicides in total.
The most-used agent combined 2,4-D and 2,4,5-T equally by weight. About 12 million gallons (about 45,000 m³) were sprayed, shipped in drums marked with an orange stripe.
TCDD entered the mixture as a contaminant of 2,4,5-T production. Its estimated soil half-life under tropical field conditions is roughly 9 to 15 years.
The VA presumes herbicide exposure for any service in the Republic of Vietnam inside these dates, regardless of specific location or duties.
Public Law 102-4 required presumptive service connection for diseases tied to dioxin exposure. The presumptive list now runs to more than a dozen conditions.
The US EPA cancelled most uses of 2,4,5-T in 1979. The other half of the mixture, 2,4-D, remains in registered use today.
Every date below is a matter of public record.
| Measure | Figure | Detail |
|---|---|---|
| Years of spraying | 1962–1971 | Operation Ranch Hand missions over South Vietnam |
| Total herbicides sprayed | ≈19 million gal (≈72,000 m³) | All herbicide agents combined |
| Agent Orange share | ≈12 million gal (≈45,000 m³) | Named for the orange stripe on 55-gal (208 L) drums |
| Mixture ratio | 50/50 by weight | 2,4-D and 2,4,5-T herbicides |
| Land sprayed | ≈5 million acres (≈2 million ha) | On the order of 10% of South Vietnam |
| TCDD soil half-life | ≈9–15 years | Under tropical field conditions |
| Presumed-exposure window | 9 Jan 1962 – 7 May 1975 | VA presumption for service in Vietnam |
| US veterans who served | ≈2.7–3.0 million | Vietnamese affected: estimates of 3–4.8 million |
A diagnosis is covered presumptively if it appears on the VA's Agent Orange presumptive list, which now runs to more than a dozen named conditions.
The list is dominated by cancers — Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, chronic B-cell leukemias, soft tissue sarcomas, respiratory cancers of the lung, larynx, trachea and bronchus, prostate cancer and bladder cancer — alongside systemic diseases such as type 2 diabetes mellitus, ischemic heart disease, AL amyloidosis and Parkinson's disease.
Three conditions carry a time limit: chloracne, porphyria cutanea tarda and early-onset peripheral neuropathy must have appeared within one year of the last exposure to qualify presumptively. Everything else on the list can be diagnosed at any point after service, which matters because dioxin-related cancers often surface decades later.
A diagnosis that is not on the list is not automatically excluded — it can still be pursued through direct service connection with supporting medical evidence — but it receives no presumption. The conditions are grouped with latency notes on the health effects page (/health-effects), and the claim mechanics are laid out on the presumptive conditions page (/presumptive-conditions).
Two presumptions do the work: service in Vietnam during the statutory window presumes exposure, and a listed diagnosis presumes the link to that exposure.
The qualifying window is fixed: service in the Republic of Vietnam at any point between 9 January 1962 and 7 May 1975. A claimant inside that window never has to prove they stood in a sprayed area — herbicide exposure is presumed by regulation.
The framework comes from the Agent Orange Act of 1991 (Public Law 102-4), which required presumptive service connection for diseases tied to dioxin exposure; the list has grown since as evidence reviews added conditions.
Denials cluster around a small set of named reasons: service dates that cannot be verified inside the window, no current diagnosis in the file, a diagnosis outside the presumptive list filed without supporting medical evidence, or a time-limited condition first documented more than one year after the last exposure.
This guide is compiled from public records: US Department of Veterans Affairs presumption rules, the Agent Orange Act of 1991 (Public Law 102-4), and widely published figures on Operation Ranch Hand. Quantities are given as approximations because source surveys differ, and no claim outcome can be predicted from this material.
Sources and further reading
Figures on this page derive from public VA materials, the text of Public Law 102-4, and widely cited estimates of the Ranch Hand campaign.