The production of dicalcium phosphate (DCP) uses phosphate rock (PR) as a raw material. Sedimentary phosphate rocks are enriched with relevant concentrations of natural radionuclides from the 238U decay chain (around 103 Bq·kg-1), leading to the need of controlling potential exposures to radiation of workers and members of the public in accordance with IAEA safety standards. Indeed, phosphate industries are classified as Naturally Occurring Radioactive Material (NORM) industries. Thus, the aim of this work is to assess the radiological risk of the workers in a DCP production plant located in the Iberian Peninsula (South-West Europe), which digests PR with hydrochloric acid. In the present study 238U, 230Th, 222Rn, 210Pb and 210Po concentrations in aerosols (indoor and outdoor areas) are reported. Aerosols showed concentrations between 0.42–92 mBq·m-3 for 238U, 0.24–33 mBq·m-3 for 230Th, 0.67–147 mBq·m-3 for 210Pb and 0.09–34 mBq·m-3 for 210Po. Long-term exposure (four months) of passive 222Rn detectors provided concentrations that ranged from detection limit (