Background: The article presents the results of the determination of the inhalable and thoracic fraction of sulfuric acid(VI) in 3 workplaces producing or processing this chemical. Material and Methods: To collect thoracic fractions of sulfuric acid(VI) Parallel Particle Impactor (PPI) was used. To isolate inhalable fraction of sulfuric acid(VI) from the air we used a sampler developed at the Institute of Occupational Medicine (IOM), United Kingdom. Parallel Particle Impactor and IOM samplers worked with pumps at a flow of 2 l/min. For the chromatographic determination of the inhalable and thoracic fraction of sulfuric acid(VI) in workplace the ion chromatography with conductometric detection was used. Results: Depending on the sampling place the concentration of thoracic fraction of sulfuric acid(VI) was: 0.0015–0.01 mg/m³ in workplace A, 0.0019–0.25 mg/m³ in workplace B, and 0.002–0.01 mg/m³ in workplace C. Of 22 tested workstations in workplace B only 7 exceeded the threshold limit value (TLV) for the concentration of thoracic fraction of sulfuric acid(VI). Conclusions: The results confirmed the utility of PPI for sampling the thoracic fraction of sulfuric acid(VI). The studies show that at 22 workstations in the establishments producing or processing sulfuric acid(VI) thoracic fraction of acid is emitted to the work environment. The collected data showed that the thoracic fraction of sulfuric acid(VI) represents on average 64% of the inhalable fraction. Med Pr 2016;67(4):509–515