Abstract
Epidemiological investigation of 475 workers exposed to dust in flax processing has shown that family susceptibility has a decisive role in the development of byssinosis in those workers. Workers whose fathers had occupational history of exposure to flax dust were more resistant to the development of the disease than those whose fathers had no such history. Such tolerance was much higher in workers whose fathers were byssinotic than those with byssinosis-free fathers. Further hereditary and immunological investigations are, however, needed.