An occupational disease or industrial disease is a long term illness caused by work. It is an important part of occupational safety and health. They are found when they are more common in a given body of workers than in other people. The first such disease to be recognised was squamous-cell carcinoma of the scrotum. It was found in chimney sweep boys by Sir Percival Pott in 1775. This led to the Chimney Sweepers Act 1788. Problems caused by accidents (such as falls by roofers) are not counted as occupational diseases.
In many countries workers can get compensation if they are affected by these diseases, sometimes from the employer and sometimes as social security.