Historical changes in chemical exposures encountered by Danish firefighters.

Objective This study aimed to demonstrate the possibility of using history science methods in occupational studies by evaluating overall historical changes in Danish firefighting modifying chemical exposures from smoke and fire trucks. Methods Data on changes in Danish firefighting after World War II were searched for in both museums and the Danish library catalogue REX, accessing collections of literature from all institutes of the University of Copenhagen and the Danish Royal Library. Results Several historical changes were identified either increasing or reducing chemical exposures in Danish firefighting. New sources of chemical exposures included more toxic smoke combustion from plastic materials introduced in the 1950s, exhaust from new diesel engines introduced in the 1960s and new assignments relating to chemical cleanups in the 1970s and traffic accidents in the 1990s. Nevertheless, several improvements in the profession`s work environment may have reduced chemical exposures, for example, mandatory use of more effective respiratory protection equipment in the 1970s, incorporation of mechanical exhaust systems in the 2000s, and filters and selective catalytic reduction (SCR) for diesel engines in the 2010s. Conclusion The data showed that the work environment in Danish firefighting has undergone several improvements during the last decades. At the same time, however, several new chemical hazards have also been introduced. Consequently, no strong conclusions as to whether Danish firefighting overall has become a less hazardous profession can be made.