**4. Conclusions**

The concentrations of individual compounds from the BTEXS in the changing room and garage are several to several dozen times higher than the concentrations of these substances in the atmospheric air outside the fire station. Both firefighters and office workers staying under measured conditions are at risk of carcinogenic exposure that exceeds an acceptable level. Among the entire BTEXS group, toluene and benzene had the highest concentrations. According to the diagnostic indicators, the combustion of various materials and fuels was the source of BTEXS inside, while the combustion of fuels and industrial activity was the source of those outside. This research provides the following conclusions:


**Author Contributions:** Conceptualization, W.R.-K. and K.B.; methodology, W.R.-K.; software, K.B.; validation, K.B., W.R.-K.; formal analysis, W.R.-K.; investigation, I.J.; resources, I.J.; data curation, K.B.; writing—original draft preparation, K.B.; writing—review and editing, W.R.-K.; visualization, K.B.; supervision, W.R.-K.; project administration, K.B. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors would like to acknowledge the Ministry of Science and Higher Education for their financial support as part of the statutory works.

**Conflicts of Interest:** The authors declare no conflict of interest.
