Effect of ammonia, urea and diammonium phosphate (DAP) on lung functions in fertilizer plant workers.

A spirometric study (FVC, FEV1 & PEFR/Min) was carried out in workers exposed to fertilizer chemicals (91) as a whole, out of which 31 were Ammonia, 30 Urea and 30 DAP plant workers, and 68 were controls belonging to the same age, sex, body surface area and socio-economic status. This study showed significant reduction in both PEFR/min and FEV1, the reduction being more in PEFR/Min., seems to indicate obstructive type of lung changes affecting the larger air-ways first, followed by bronchospasm. But FVC showed a significant reduction only after more than 10 years of exposure, probably causing restrictive changes only after prolonged exposure. Out of the 3 chemicals, DAP affected all the 3 parameters most, followed by Ammonia and Urea affected the least.