Accoding to the Veterans Affairs:
illnesses believed to be caused by contact with Agent Orange
AL amyloidosis: A rare illness that happens when an abnormal protein (called amyloid) builds up in your body’s tissues, nerves, or organs (like your heart, kidneys, or liver) and causes damage over time
Chloracne (or other types of acneform disease like it): A skin condition that happens soon after contact with chemicals and looks like acne often seen in teenagers. Under our rating regulations, it must be at least 10% disabling within 1 year of contact with herbicides.
Diabetes mellitus type 2: An illness that happens when your body is unable to properly use insulin (a hormone that turns blood glucose, or sugar, into energy), leading to high blood sugar levels
Ischemic heart disease: A type of heart disease that happens when your heart doesn’t get enough blood (and the oxygen the blood carries). It often causes chest pain or discomfort.
Parkinson’s disease: An illness of the nervous system (the network of nerves and fibers that send messages between your brain and spinal cord and other areas of your body) that affects your muscles and movement—and gets worse over time
Peripheral neuropathy, early onset: An illness of the nervous system that causes numbness, tingling, and weakness. Under our rating regulations, it must be at least 10% disabling within 1 year of contact with herbicides.
Porphyria cutanea tarda: A rare illness that can make your liver stop working the way it should and can cause your skin to thin and blister when you’re out in the sun. Under VA’s rating regulations, it must be at least 10% disabling within 1 year of contact with herbicides.
Therefore, COPD is not beleieved to be caused by Agent Orange.