Hundreds of thousands of veterans who served in Iraq and Afghanistan are dealing with breathing problems — asthma, COPD, constrictive bronchiolitis — and a VA claims system that repeatedly denied them. The PACT Act changed some of that. But even with expanded presumptives, many veterans with burn pit-related respiratory conditions still need a strong nexus letter to win their claim. This guide tells you exactly what that letter needs to say, who should write it, and how to build an evidence package that VA raters cannot ignore.
Military burn pits were massive open-air burning sites used to dispose of waste at FOBs and COPs throughout Iraq, Afghanistan, and elsewhere in Southwest Asia. Joint Base Balad in Iraq was one of the largest — at peak operation, its burn pit covered 10 acres and burned 140 tons of waste daily. Similar operations existed at Bagram Air Base, FOB Salerno, Camp Taji, Camp Victory, and hundreds of smaller installations.
The smoke from these fires contained a toxic mixture of compounds that don't belong anywhere near human lungs: polycyclic aromatic hydrocarbons (PAHs), dioxins, furans, volatile organic compounds (VOCs), heavy metals, particulate matter (PM2.5 and PM10), and incompletely combusted materials from plastics, chemicals, medical waste, and ordnance. Soldiers who worked, slept, or trained near these pits inhaled this mixture continuously — sometimes for months or years.
The medical literature on burn pit-related respiratory disease is growing rapidly. Studies published in peer-reviewed journals including American Journal of Respiratory and Critical Care Medicine, Chest, and Environmental Health Perspectives document multiple distinct pathological responses to burn pit smoke:
The absence of a diagnosis in your service treatment records does not mean you weren't injured during service. Many veterans were told their symptoms were anxiety, deconditioning, or "normal" respiratory irritation. The science confirming the connection between burn pit exposure and chronic lung disease developed largely after these veterans left service. Your nexus letter physician can explain this latency and chronology to VA.
The Sergeant First Class Heath Robinson Honoring our Promise to Address Comprehensive Toxics (PACT) Act, signed in August 2022, substantially expanded VA's presumptive service connection for toxic exposure-related conditions. Understanding what is and isn't covered is critical to choosing your claims strategy.
Under the PACT Act, VA established a presumption of service connection for veterans who served in covered locations after August 2, 1990 (Southwest Asia, Afghanistan, Djibouti, Syria, and other designated areas) for the following conditions, among others:
Asthma and COPD are NOT automatically presumptive under the PACT Act as of 2026. However, this does not mean these conditions can't be service-connected — it means you need to prove the connection rather than relying on a presumption.
If you haven't already registered with VA's Airborne Hazards and Open Burn Pit Registry (AHOBPR), do so now at va.gov before filing your claim. Registration documents your self-reported exposure and creates an official VA record of your burn pit service. Importantly, VA will use your registry data in the claims evaluation. Registering is free and takes about 30 minutes.
Even veterans whose conditions might qualify as presumptive sometimes benefit from a nexus letter. If VA disputes whether you served in a covered location, whether your condition meets the presumptive criteria, or whether your current respiratory diagnosis is actually the covered condition, a physician's expert opinion can resolve those disputes. Additionally, a nexus letter can establish a higher initial rating by documenting the full severity of your condition and its relationship to your military service.
Your nexus letter physician needs to document your condition in the context of VA's rating criteria. The rating determines how much you get paid — so understanding the rating thresholds matters.
| Rating | Criteria | 2026 Monthly Rate (No Dependents) |
|---|---|---|
| 10% | FEV1 of 71–80% predicted, or DLCO of 66–80% predicted | $180.42 |
| 30% | FEV1 of 56–70% predicted, or DLCO of 56–65% predicted; or daily inhalational or oral bronchodilator therapy; or inhalational anti-inflammatory medication | $552.47 |
| 60% | FEV1 of 40–55% predicted, or more than once-a-week attacks; requiring corticosteroids | $1,435.02 |
| 100% | FEV1 less than 40% predicted, or more than one attack per week with episodes of respiratory failure | $3,938.58 |
| Rating | FEV1 % Predicted | 2026 Monthly Rate (No Dependents) |
|---|---|---|
| 10% | 71–80% | $180.42 |
| 30% | 56–70% | $552.47 |
| 60% | 40–55% | $1,435.02 |
| 100% | <40% | $3,938.58 |
The ratings are heavily weighted toward objective pulmonary function test results. Before your nexus letter appointment, ensure you have recent spirometry results (within 12 months) that show your FEV1 percentage. Your physician needs these numbers to write a rating-aware nexus opinion. Use our free rating estimator to get an idea of where your PFT results fall.
Burn pit respiratory claims have historically had among the highest denial rates of any VA disability category. Understanding why helps you counter these reasons before they appear in a rating decision.
The most common denial reason. VA raters note that there is no diagnosis of asthma or COPD in the service treatment records and conclude there's no in-service event. This logic is fundamentally flawed for burn pit conditions — the disease develops over years, not instantly. Your nexus letter physician must explicitly address the latency issue and explain that the absence of an in-service diagnosis is consistent with the known pathophysiology of burn pit-related lung disease.
C&P examiners who are not pulmonologists frequently write negative nexus opinions because they don't have the specialized knowledge to understand the connection between specific particulate exposures and specific respiratory pathology. A VA generalist examiner writing "less likely than not" for a burn pit asthma claim is not the final word — it creates a conflict of evidence that a private nexus letter can resolve in your favor.
If you smoke or have smoked, VA raters often attribute your COPD to tobacco rather than burn pit exposure. A strong nexus letter physician will address this directly — discussing the additive effects of smoke exposure, the difference in the type of COPD seen in burn pit veterans versus tobacco smokers, and the fact that even smoking veterans experienced accelerated FEV1 decline from burn pit exposure that goes beyond what tobacco alone would predict.
VA needs to know where you were and when. If your service records don't clearly place you at a known burn pit location, you need to build that case independently. Buddy statements from fellow service members, photographs, deployment orders, and unit logs can all establish your proximity to burn pits. Many veterans also qualify through the AHOBPR registry data they submitted.
For an asthma or COPD claim linked to burn pit or inhalation exposure, your nexus letter needs to be more thorough than a standard nexus letter. Here's the complete checklist:
Ideally a board-certified pulmonologist (internal medicine with pulmonary subspecialty). At minimum, a board-certified internist or occupational medicine physician with documented experience in toxic exposure-related respiratory disease. The physician's credentials should appear in the letterhead.
The letter must confirm the current diagnosis — asthma (DC 6602), COPD (DC 6604), or both — and reference the supporting diagnostic data (PFT results, spirometry values, imaging if relevant).
The physician should reference the specific exposures documented in your service records and self-report: the burn pit locations, duration, frequency, and types of materials burned. If you're a PACT Act-eligible veteran, the letter should reference your qualifying service locations.
This is the heart of the nexus letter. The physician explains exactly how chronic exposure to fine particulate matter (PM2.5), combustion byproducts (PAHs, dioxins, VOCs), and thermal injury causes airway inflammation, airway remodeling, bronchospasm, and the characteristic pathological changes seen in burn pit-exposed veterans. The letter should cite specific medical literature — peer-reviewed studies, not just general statements.
The letter must conclude with a clear probability statement: "It is at least as likely as not that [veteran]'s [asthma/COPD] was caused by [or aggravated beyond its natural progression by] [specific exposures] during [veteran]'s military service at [locations] from [dates]."
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Before you can get a nexus letter, you need to document that you were actually exposed. This is especially important for veterans whose service records don't explicitly mention burn pit proximity. Here's how to build your exposure record:
Register with VA's Airborne Hazards and Open Burn Pit Registry if you haven't already. VA will use your registry data in your claim. The registry asks about specific exposures, locations, and symptoms. Complete it thoroughly.
Request your complete STRs from the National Personnel Records Center or through your VA file. Look for any documentation of respiratory symptoms during deployment — coughing, wheezing, shortness of breath, "deployment asthma" or "deployment cough." Even a mention of respiratory symptoms in a sick call visit strengthens your claim.
Your deployment orders show where and when you served. Cross-reference your deployment locations with known burn pit sites documented by the DoD's Airborne Hazard and Open Burn Pit Surveillance system or the Congressional Research Service's reports on burn pit locations.
Fellow veterans who served with you can submit written statements documenting your proximity to burn pits, the frequency of exposure, and any symptoms they observed. These lay statements are legitimate evidence under 38 CFR 3.303(a) and support the factual foundation your nexus letter physician relies on. Learn how to get a properly formatted buddy statement here.
Not every veteran with service-connected respiratory disease was a burn pit veteran. VA recognizes multiple other toxic inhalation exposures that can support asthma or COPD claims:
Veterans who served in Kuwait during 1990–1991 were exposed to massive oil well fire smoke from the more than 700 fires set by Iraqi forces during the Gulf War. The oil well smoke was thick with sulfur dioxide, benzene, hydrogen sulfide, and fine particulate matter. Gulf War veterans with respiratory disease may qualify for both Gulf War presumptive coverage and direct service connection based on oil well fire exposure.
Veterans who worked on flight decks, at airfields, or in aircraft maintenance were routinely exposed to JP-4 and JP-8 jet fuels and their combustion products. JP-8 contains benzene, naphthalene, and other aromatic hydrocarbons with known respiratory toxicity. Navy and Air Force veterans with flight deck exposure should document this as a specific exposure in their nexus letter.
Veterans who worked in industrial settings — shipyards, maintenance facilities, chemical storage areas — may have been exposed to isocyanates, chlorine, ammonia, or other respiratory irritants. Occupational medicine physicians are particularly well-suited to write nexus letters connecting these specific chemical exposures to current respiratory conditions.
Southwest Asia sandstorms contain fine desert particulate matter, microbial agents, and — in some regions — heavy metals from disturbed soil. Research documents elevated rates of respiratory illness in veterans with high sandstorm exposure even without proximity to burn pits.
For asthma and COPD claims linked to toxic exposure, you need a physician who:
Specialized nexus letter services like REE Medical maintain networks of physicians who meet these criteria and write letters specifically structured for VA claims. If you prefer to use your own civilian pulmonologist, provide them with: (1) the five required elements of a nexus letter (as described above); (2) relevant published studies on burn pit respiratory disease; and (3) a clear written request asking for a formal medical opinion, not just a clinical note.
You have two paths to service connection for burn pit-related asthma or COPD. Understanding which applies to your situation shapes your entire claim strategy:
If your pulmonary function tests and biopsy results (if obtained) indicate constrictive bronchiolitis, file under the PACT Act presumptive. You must have: (a) served in a covered location after August 2, 1990, and (b) a current diagnosis of constrictive bronchiolitis. No nexus letter is technically required for a presumptive claim — but a nexus letter can still help establish the diagnosis and severity, and can address any VA disputes about whether your condition meets the presumptive criteria.
For asthma or COPD that doesn't qualify as presumptive, file under direct service connection (38 CFR 3.303). You need: (a) a current diagnosis, (b) documented in-service exposure, and (c) a nexus letter establishing the causal or aggravation link. This is where a strong pulmonologist nexus letter is indispensable.
Before filing, check our PACT Act eligibility screener to confirm which path applies to your service history and diagnosis. Then review the complete burn pit VA claims guide for the full picture. If you've already been denied and are appealing, see our VA claims denial appeals guide.
Asthma is not automatically presumptive under the PACT Act as of 2026. Constrictive bronchiolitis and certain cancers are presumptive. Asthma and COPD require direct service connection evidence — which is where a well-written nexus letter becomes critical. However, the PACT Act substantially expanded the range of covered exposures that can be cited as the basis for a direct service connection claim.
Asthma is rated under Diagnostic Code 6602. COPD is rated under DC 6604. Constrictive bronchiolitis may be rated under DC 6699-6604 (analogous to COPD) or another analogous code. Your nexus letter physician should address the specific diagnostic code and the functional impairment criteria it uses — primarily FEV1 percentage of predicted normal.
Yes, if your pulmonary function tests support it. A 100% rating under DC 6602 requires FEV1 of less than 40% predicted, or more than one attack per week with episodes of respiratory failure. This is severe disease — but many veterans with significant burn pit exposure and years of progressive decline do meet this threshold. Use our rating estimator tool to get a baseline assessment.
This is a very common denial reason, but it's challengeable. Your nexus letter physician should specifically address the confounding effect of tobacco and distinguish the burn pit-related component of your respiratory disease. Research supports that burn pit exposure causes respiratory disease independently of tobacco history and causes accelerated FEV1 decline above what tobacco alone predicts. A Supplemental Claim with a physician's rebuttal of the tobacco argument can overturn this denial.