The VA Lists Seven Chemicals of Concern. The Navy Found More Than Forty.
For years, the Department of Veterans Affairs (VA) has recognized seven chemicals of concern associated with exposures from the Shinkampo Incinerator Complex at Naval Air Facility (NAF) Atsugi.
According to the VA's M21-1 Adjudication Manual and other VA exposure summaries:
"Identified chemicals included: chloroform, 1,2-dichloroethane (1,2-DCE), methylene chloride, trichloroethylene (TCE), chromium, dioxins and furans, and particulate matter."
At first glance, this appears to be a complete list of hazardous contaminants associated with the Shinkampo Incinerator Complex.
However, the Navy's own environmental investigations document a much broader range of contaminants.
This matters as the VA's adjudication manual and exposure summaries do not identify this as an abbreviated summary, nor do they clearly direct readers to a more comprehensive contaminant list elsewhere in VA guidance or records.
What the Navy Found
Between 1988 and 2001, the Navy conducted multiple environmental sampling campaigns and three health risk assessments to evaluate emissions from the Shinkampo Incinerator Complex.
The Navy's final 2002 Health Risk Assessment identified approximately 269 chemical analytes and labeled more than 40 as contaminants of concern in the ambient air due to maximum concentrations exceededing EPA screening levels used at the time.
Earlier investigations also documented contaminants of concern:
The discrepancy raises an important question:
Why does the VA’s exposure summaries and adjudication guidance only reference seven chemicals when the Navy's own investigations documented many more?
Why the Difference Matters
Chemicals identified in VA exposure summaries and adjudication guidance can influence how disability claims are developed and evaluated. A veteran may attribute a medical condition to a contaminant documented in the Navy's environmental investigations, yet that contaminant may not appear anywhere in the VA's guidance.
If an adjudicator relies primarily on the VA's exposure summary—and does not independently review the Navy's underlying environmental reports—they may conclude that the veteran was not exposed to the claimed contaminant. That determination could affect whether the exposure is recognized as a Toxic Exposure Risk Activity (TERA) and, in turn, whether the veteran receives a VA medical examination and nexus opinion under the TERA framework.
The same concern extends to medical evaluations. If a VA examiner or other healthcare professional relies primarily on the VA's exposure summary, they may be unaware that a veteran was potentially exposed to additional contaminants documented in the Navy's environmental investigations. An incomplete exposure history can influence differential diagnoses, clinical evaluations, medical opinions, and nexus determinations.
Even when additional evidence is ultimately considered, incomplete exposure guidance increases the risk that relevant documented exposures may be overlooked during claim development or medical evaluation, potentially affecting both a veteran's disability claim and their medical care.
If the VA's list were presented as a brief summary, or if it clearly directed adjudicators and medical examiners to the Navy's complete contaminant lists, the discrepancy would be less concerning. It does neither.
For veterans who served at NAF Atsugi, ensuring that the VA's guidance accurately reflects the Navy's documented findings is more than a technical correction. It helps ensure that Toxic Exposure Risk Activities are properly recognized, that medical evaluations are based on the most complete exposure history available, and that disability claims are developed and decided using the best available scientific evidence.
The Navy's 2002 Chemical List Was Accurate—But Not Comprehensive
While the Navy's final 2002 Health Risk Assessment identifies a more thorough list of chemicals, it does have a couple of limitations.
First, its quantitative risk analysis relied primarily on environmental sampling conducted 1998 to 1999, rather than the full body of sampling collected throughout the facility's operational history.
While this is not unsual for a health risk assessment, this matters because the Shinkampo Incinerator did not operate under consistent conditions throughout its history. Over two decades, it evolved from an uncontrolled open burn pit and poorly controlled incinerator into a facility with progressively improved pollution controls before closing in 2001.
The open burn pit closed in 1984.
New incinerators were installed in 1987, 1991, and 1993.
The first wet-quench scrubber was installed on Stack No. 2 in 1991.
Additional scrubbers were installed on the remaining stacks by 1995.
Extended quench sections and baghouse filters were added to all three units in 2000.
Operational practices also changed. Navy field reports from the mid-to-late 1990s documented repeated instances in which the operator interferred with sampling efforts. The complex reduced throughput, temporarily shut down equipment, or burned cleaner waste streams during environmental monitoring, with emissions reportedly increasing again after visible sampling equipment was removed.
Because emissions varied with the waste being burned, operating conditions, and pollution controls in place, no single sampling campaign can fully characterize the range of exposures experienced over the facility's lifetime. Sampling conducted during 1998–1999 may therefore not fully reflect conditions during earlier years, particularly before effective emission controls were installed. During that period, emissions for some contaminants may have been an order of magnitude (approximately 10-fold) higher than those measured after pollution-control upgrades.
Additionally, the Health Risk Assessment itself is well over two decades old. It largely relied on the toxicological data, exposure assumptions, analytical methods, and EPA guidance from the 1980s and 90s. Since 2002, environmental health science has advanced substantially, with new and updated toxicity values, screening criteria, and a better understanding of long-term and cumulative chemical exposures.
VFEA’s Updated Analysis
Although VFEA cannot formally update the Navy's Health Risk Assessment, we can evaluate the Navy's historical environmental data using current EPA screening levels and health-protective criteria. To provide the most comprehensive review possible, VFEA reviewed all publicly available Navy environmental investigations rather than relying solely on the 1998–1999 sampling campaign used in the Navy's final risk assessment.
For each contaminant identified in the historical sampling records, VFEA compared the highest documented concentration reported across all available studies with current EPA Regional Screening Levels (RSLs) and National Ambient Air Quality Standards (NAAQS). Using the maximum measured concentration provides a conservative, worst-case screening approach that captures the full range of contamination documented during the facility's operation.
This analysis is not intended to estimate an individual's exposure, predict disease risk, or replace a formal human health risk assessment. Rather, it serves as a screening-level evaluation designed to identify contaminants that reached concentrations warranting further consideration under today's environmental health standards.
By applying modern EPA toxicity values and screening criteria to the Navy's historical measurements, VFEA provides an updated assessment of documented chemical contamination at NAF Atsugi that reflects both the full body of available environmental sampling data and the significant advances in environmental health science since 2002. The resulting contaminant lists are intended as a research and educational resource for veterans, families, clinicians, researchers, and policymakers.
VFEA Findings
VFEA’s analysis found nearly 290 chemical analytes for air and soil between all avilable samplings. Based on current EPA screening guidelines and regulations, approximately 83 were identified as contaminants of concern.
Ambient Air
70 contaminants of concern were identified in the ambient air
38 chemicals exceed EPA residential air Regional Screening Levels (RSLs) for cancer
53 chemicals exceed EPA residential RSLs for non-cancer effects
6 chemicals exceed EPA National Ambient AIr Quality Standards for criteria pollutants
Soil
21 contaminants of concern were identified in the soil
8 chemicals exceed EPA residential soil RSLs for cancer
16 chemicals exceed EPA residential soil RSLs for non-cancer effects
Takeaways
At a minimum, the Department of Veterans Affairs should update its M21-1 Adjudication Manual and related exposure guidance to reflect the contaminants identified in the Navy's own 2002 Comprehensive Health Risk Assessment, rather than continuing to reference only seven chemicals.
Ideally, the Department of the Navy should conduct an updated Health Risk Assessment for the Shinkampo Incinerator Complex using current toxicological data and modern risk assessment methodologies. The Department of Veterans Affairs should then integrate the updated findings into its exposure guidance, adjudication policies, and clinical systems to ensure veterans' claims and healthcare decisions are informed by the best available scientific evidence.
The existing assessment is now more than two decades old and reflects the scientific knowledge, exposure assumptions, toxicological data, and regulatory guidance available at the time. Since then, environmental health science has advanced considerably. A modern reassessment would provide a more accurate characterization of historical exposures, better inform healthcare and disability benefit decisions, guide future research, and improve the evidence base used by veterans, clinicians, researchers, and policymakers.
The veterans and families who lived and worked at NAF Atsugi deserve an updated exposure assessment—and a VA exposure record—that reflects both the full scope of the Navy's historical environmental data and the current state of environmental health science.