Constrictive Bronchiolitis (Burn Pit Exposure)

DC 6600Respiratory38 CFR 4.97, DC 6600

A condition where the smallest airways in the lungs (bronchioles) become scarred and narrowed, restricting airflow. Strongly associated with burn pit and toxic exposure during deployment. Often requires surgical lung biopsy for definitive diagnosis because standard PFTs may appear deceptively normal. The VA rates constrictive bronchiolitis based on lung function tests.

How the VA rates this condition

The VA rates this condition based on objective clinical measurements and test results. The examiner will use standardized tests or lab values to determine the severity of your condition rather than relying primarily on subjective symptom reports.

Diagnostic code

DC 6600

Rating range

10% – 100%

Rating levels

Rating criteria are defined in 38 CFR 4.97, DC 6600. This guide presents a plain-language summary and is not a substitute for the full regulatory text. Always consult a VSO or VA-accredited attorney for case-specific advice.

Rating Levels

Your lung function tests show FEV-1 less than 40 percent predicted, or FEV-1/FVC less than 40 percent, or DLCO (SB) less than 40 percent predicted, or you require outpatient oxygen therapy, or you have cor pulmonale or pulmonary hypertension.

What the VA looks for

FEV-1 less than 40% predicted
DLCO less than 40% predicted
Outpatient oxygen therapy prescribed
Cor pulmonale or pulmonary hypertension documented
Surgical lung biopsy confirming constrictive bronchiolitis
Episodes of acute respiratory failure

Common Pitfalls

⚠Relying solely on standard PFTs — constrictive bronchiolitis can show deceptively normal spirometry. Request full PFTs including lung volumes, DLCO, and expiratory CT imaging to reveal air trapping.
⚠Not pursuing surgical lung biopsy when clinically indicated — constrictive bronchiolitis is a pathological diagnosis that often requires biopsy for definitive confirmation, which significantly strengthens your claim.
⚠Not enrolling in the Airborne Hazards and Open Burn Pit Registry — registry enrollment documents your exposure and supports PACT Act presumptive service connection.
⚠Not documenting specific deployment locations and burn pit proximity — include base names, dates, and descriptions of what was burned (trash, medical waste, chemicals, munitions).

Related DBQ Forms

DBQ Respiratory Conditions (other than Tuberculosis and Sleep Apnea)

View evidence checklist →See secondary conditions →

Condition Rating Guides

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Constrictive Bronchiolitis (Burn Pit Exposure)

How the VA rates this condition

Diagnostic code

DC 6600

Rating range

10% – 100%

Rating levels

Rating Levels

What the VA looks for

FEV-1 less than 40% predicted
DLCO less than 40% predicted
Outpatient oxygen therapy prescribed
Cor pulmonale or pulmonary hypertension documented
Surgical lung biopsy confirming constrictive bronchiolitis
Episodes of acute respiratory failure

Common Pitfalls

⚠Relying solely on standard PFTs — constrictive bronchiolitis can show deceptively normal spirometry. Request full PFTs including lung volumes, DLCO, and expiratory CT imaging to reveal air trapping.

⚠Not pursuing surgical lung biopsy when clinically indicated — constrictive bronchiolitis is a pathological diagnosis that often requires biopsy for definitive confirmation, which significantly strengthens your claim.

⚠Not enrolling in the Airborne Hazards and Open Burn Pit Registry — registry enrollment documents your exposure and supports PACT Act presumptive service connection.

⚠Not documenting specific deployment locations and burn pit proximity — include base names, dates, and descriptions of what was burned (trash, medical waste, chemicals, munitions).