Emerging Evidence Connects Agent Orange to Bone Marrow Disorders in Veterans

During the Vietnam War, about 2.6 million U.S. service members were potentially exposed to Agent Orange (AO). It was extensively sprayed over the jungles of Southeast Asia to remove foliage that could conceal enemy combatants, and it was also sprayed in the Korean Demilitarized Zone in the late 1960s.

The defoliant contains one of the most dangerous industrial chemicals ever produced, a toxic form of dioxin - a recognized carcinogen by the WHO, the EPA, and other global agencies. When concerns about illnesses in exposed service members grew throughout the 1970s and 1980s, Congress passed the Agent Orange Act of 1991, which resulted in the first report by the Institute of Medicine (IOM) that summarized studies showing that certain diseases occurred more frequently in exposed veterans than in unexposed populations. Previous studies have tied AO to blood cancers, including:

• lymphoma
• multiple myeloma
• leukemia

Following the IOM's findings, the VA began providing disability compensation for veterans who develop diseases linked to AO exposure, recognizing cancers such as:

• bladder cancer
• chronic B-cell leukemia
• Hodgkin's disease
• multiple myeloma
• Non-Hodgkin's lymphoma
• prostate cancer
• lung cancer
• soft tissue sarcomas

However, the VA doesn't include the following on the list of presumptive conditions:

• osteosarcoma
• chondrosarcoma
• Kaposi's sarcoma
• mesothelioma

The IOM updates its list of AO-associated diseases every two years, which the VA refers to as "presumptive diseases." It encompasses many hematologic malignancies but excludes myelodysplastic syndrome (MDS).

Veterans' Agent Orange Exposure: a Higher Risk of MDS

Myelodysplastic syndrome (MDS) is a rare form of bone marrow cancer caused by the bone marrow producing defective blood cells, which often die prematurely, leading to low blood cell counts. The condition develops slowly over time in about one-third of patients, and can progress to acute myeloid leukemia (AML), another cancer of the bone marrow. MDS has different subtypes, which affect specific blood cells:

• red blood cells
• white blood cells
• platelets

Depending on the subtype, a veteran with MDS may develop:

• anemia (low red blood cell count)
• leukopenia (low white blood cell count)
• thrombocytopenia (low platelet count)

Based on which type of cell is most affected, MDS and low blood cell counts can lead to a variety of symptoms, including:

• weakness or fatigue
• dizziness
• shortness of breath
• inability to fight infections
• skin discoloration
• rashes and hives
• easy bruising
• excessive bleeding
• blood in urine or stool

Because a clear connection to MDS had not been established, it created real barriers for veterans seeking care and disability benefits. Only one prior study examined this link, but it lacked confirmed diagnoses and complete exposure data. Today, veterans who were 22 years old in 1968 (the average age at peak deployment) are reaching the age of highest risk for MDS. Because MDS is not on the presumptive list, exposed veterans must provide additional evidence - typically a nexus letter from a doctor linking their MDS to AO exposure to have their condition recognized as service-connected.

Change Through the New Study's Findings

For the first time, the National MDS Natural History Study, presented at the 2025 ASH Annual Meeting, provides strong evidence supporting that connection. This nationwide, prospective study examined data from 2,115 participants, including 130 who self-reported AO exposure. The results show that compared to unexposed participants, those exposed were:

• diagnosed with MDS at a younger age
• had a higher number of harmful mutations
• were more predisposed to high-risk genetic patterns

Notably, hazardous genetic patterns are observed in MDS cases linked to toxic exposure. Moreover, the study draws on detailed genetic information from bone marrow samples and environmental exposure histories, representing the first effort to link confirmed MDS diagnoses with documented AO exposure.

Even if this research doesn't add MDS to the VA's presumptive disease list, it is essential support for veterans and their doctors in establishing service connection. Former service members can now use this evidence to strengthen their disability claims - a welcome help given the controversy in recent years about whether AO-exposed veterans who develop MDS are entitled to compensation under the Agent Orange Act.

The research team plans to verify its results using national veteran databases and to publish them in a peer-reviewed journal. Until then, these findings presented at medical meetings should be considered preliminary.

Even so, if a veteran was previously denied a VA claim for MDS, they can reapply by providing new evidence that wasn't available at the time. The 2025 MDS study showing a link between AO and MDS counts as this new evidence. Veterans also need a letter from their doctor explaining how their MDS is connected to their service. Once the VA receives this information, it will reconsider the claim, and the new evidence may improve the chances of approval.

VA Benefits for AO or Other Herbicide Exposure

For thousands of men and women who served in the military during the Vietnam War era, AO exposure may be at the root of serious illnesses impacting their health today, including MDS. Older age also counts as a risk factor in developing the disease, as most patients with a form of MDS are over 60 years old.

Veterans who were exposed to AO or other herbicides during service may be eligible for VA benefits, such as:

• health care -in addition to comprehensive medical benefits, Vietnam veterans and those who served in other areas where AO was sprayed may be eligible for a free exam through the Agent Orange Registry health exam.
• disability compensation - veterans' eligibility depends on in-service AO exposure, a subsequent disability, and an other-than-dishonorable discharge.
• benefits for children with birth defects - Biological children of Vietnam or Korea veterans who have certain birth defects may be eligible for VA compensation, health care, and vocational training.
• survivors' benefits - Surviving spouses, dependent children, and dependent parents of in-service AO-exposed veterans who died because of diseases related to their exposure may be eligible for health care, compensation, education, and home loan benefits

Veterans with qualifying service are presumed to have been exposed to AO. Those who develop a cancer not on the VA's presumptive list can still apply for benefits, but they need to submit more evidence. The DOD provided VA with a list of dates and locations for herbicide testing and storage for reference.

If your diagnosed condition isn't on the list of presumptive conditions, you'll also need to provide at least one of these types of evidence:

• a document that shows the problem started during service or got worse because of our military years, or
• a medical paper stating that your illness is caused by AO exposure, or scientific proof, which may be an article from a medical journal or a published research study.

Providing Assistance to Toxic-Exposed Veterans

The risks of toxic or chemical exposure during military service have evolved over time. The First World War introduced chemical warfare agents as a threat to veterans' health, and the Vietnam War era added various toxic substances to the mix, including Agent Orange. Today, service members are more likely to face hazardous chemical spills, whether on military bases or while deployed abroad.

However, exposure to hazardous materials is not limited to combat zones. It can also occur during training exercises, routine military duties, or through environmental sources such as contaminated groundwater. If veterans can demonstrate that their disability resulted from toxic or chemical exposure during active military service, they may qualify for VA benefits. We can assist in connecting you with legal professionals who specialize in toxic exposure cases and have significant experience in this area.