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  • By Mar-Vic Cagurangan

Yale report: Soil sampling not effective in detecting Agent Orange

But clinic says most evidence back veterans' claims of exposure

Detecting residues of Agent Orange on Guam has proved challenging, but the weight of the evidence strongly shows that veterans who served on Guam from 1962 to 1975 were exposed to herbicides, according a white paper recently released by the Veterans Legal Services Clinic at Yale Law School.

The white paper, released May 8, named some factors that contribute to the potential failure of soil sampling to confirm or disprove the presence of Agent Orange on Guam.

"The half-lives of Agent Orange’s two chemical constituents—nbutyl 2,4-D and n-butyl 2,4,5-T—range from days to a few months," it said. "Guam’s tropical climate, with intense rain, winds, and sunlight coupled with frequent typhoons, accelerates deterioration to further limit their time-range for detectability."

More than five decades years after the time period in question, 2,4-D or 2,4,5-T soil sampling is no longer a viable method for confirming or disproving the presence of Agent Orange on Guam, the white paper said.

"Agent Orange’s own chemical composition and the scope of time elapsed since application limit the practicality of sampling techniques," the report said. "Short half-lives for detectability, as well as easily explicable alternative origins on Guam— namely commercial herbicides and waste incineration—undermine drawing any definitive conclusions."

In October last year, Brian Moyer, Florida resident and founder of the Agent Orange Survivors of Guam, came back to the island to assist a research team from the U.S. Environmental Protection Agency in collecting soil samples from several spots where veterans said they sprayed Agent Orange. The team sampled soil NCS, Route 3, Potts Junction and Santa Rita. Findings from this research have yet to be released.

Last year's fact-finding trip was a follow-up to EPA's research in November 2018, which yielded inconclusive results. ADVERTISEMENT

Even if the government were to test for 2,3,7,8-TCDD, the white paper said, methodological challenges would still pose challenges

"A positive result for 2,3,7,8-TCDD would confirm the presence of a toxic health threat to veterans and likewise increase the probability of Agent Orange presence, but without meaningful documentary or other evidence ruling out alternative sources of environmental pollution, it would remain difficult to definitively prove that any detected concentrations of 2,3,7,8-TCDD are attributable to Agent Orange specifically," the white paper said.

At any rate, the VLSC report concluded that the veterans generally satisfy the Veterans Affairs' legal standards that support presumptive service connection for diseases associated with herbicides.

The report was based on analyses of scientific and lay evidence, including the sworn statements of numerous veterans who have already been credited by the Board of Veterans Appeals.

Despite numerous accounts of Agent Orange use on Guam, the Department of Defense has repeatedly denied such claims, thus defeating the veterans' fight for recognition of their in-service disabilities. The BVA has been inconsistent with its decisions on claims filed by Guam veterans —some were approved, others were denied.


In a report released in November 2018, the Guam Accountability Office said at least one ship carrying Agent Orange stopped at Apra Harbor on its way to Vietnam but no record exists showing that any cargo actually landed. The GAO report said available shipment documentation indicates that nearly all of the Agent Orange procured was either used in U.S. military operations in Southeast Asia, used for testing, damaged, or destroyed.

But the Yale clinic's white paper countered that incomplete or destroyed DoD records do not disprove the use of Agent Orange on Guam. "Neither DoD’s incomplete storage and shipping records nor inherently limited soil testing methodologies can be treated as negative evidence in assessing an individual veteran’s claim for disability compensation for Agent Orange-related illnesses through service on Guam," the VLSC said. "Individual veterans cannot lawfully be penalized for DoD’s incomplete recordkeeping and retention."

The white paper noted that during the Vietnam conflict, Guam became “the site of the most immense buildup of air power in history.”

"Beyond housing shortages, the rapid airpower buildup in Guam presented an acute need to control fire risks using herbicides. With annual rainfall above 90 inches per year (more than quadruple the annual average at Pearl Harbor and nearly double that of Hanoi, Vietnam), the threat of brush fires during Guam’s dry season was a paramount concern for the island’s military leadership during the Vietnam conflict.

The white paper cited a Navy newspaper's front page story on March 21, 1969, reporting a water shortage after firefighters and local volunteers responded to more than 40 fires in a single week.

"Because of the unique climate conditions of the island, the high concentration of key military assets, and significant water shortages, the need to manage vegetation with herbicides was far greater in Guam than in other military installations elsewhere in the United States or Southeast Asia," the white paper said.

The clinic's report also noted that official government accounts indicated widespread mishandling of herbicides that were reportedly sprayed "often without documentation or attempts to mitigate public health risks."

It cited, for example, a 1985 environmental impact statement related to Air Force cleanup efforts in Guam, which the white paper said proved concrete examples of herbicide and pesticide mishandling by military units or activities on the island, including a 100-gallon herbicide spill from a tank trailer near Tarague Beach in 1972 and a 1,500-gallon herbicide spill at the Harmon tank annex in 1984

"With respect to the 1972 herbicide spill at Tarague, the EIS notes that' no report of this incident or related action is available,'" the white paper said.

"In 1996, USAF—with the support of EPA—decided to undertake soil testing to evaluate the potential presence of hazardous wastes at the dumpsites. This testing revealed numerous sites with concentrations of 2,3,7,8- TCDD/dioxin exceeding EPA risk standards."

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