Minimum duration of developing coal miners pneumoconiosis is -: (A) 2-4 years, (B) 4-6 years, (C) 8-10 years, (D) More than 10 years
Answer is D. - The coal miners pneumoconiosis has two phases; first phase is simple pneumoconiosis which is associated with little ventilatory impairment. - this phase may require about 12 years of work exposure for its development. - second phase is characterized by progressive massive fibrosis Reference: Park's textbook of preventive and social medicine, 23rd edition, pg no:806 <\p>