Trends of occupational exposure to chemical agents in Finland in 1950-2020

Introduction: The aim of this study was to quantitatively estimate the long-term trends of occupational exposure to chemical agents in Finland for surveillance, prevention, and risk assessment purposes.

Methods: We studied trends by utilizing the Finnish job-exposure matrix (FINJEM), which includes occupation-specific estimates of the prevalence P (percent of employed) and average level L (agent-specific units) of inhalation exposure to chemical agents at different time periods. We used FINJEM data to calculate national estimates of the numbers of exposed workers (N exp), and the prevalence of and level of exposure to 41 chemical agents in 1950, 1970, 1990, and 2008. We also estimated the prevalence of employees exposed to levels exceeding 50% of the Finnish occupational exposure limit (OEL) (P high) and national occupational inhalation exposure (NOIE = N exp × L). Future exposures in 2020 were estimated according to the predicted change of the occupational structure of the labor force and the observed agent-specific exposure trends in 1990-2008. We estimated dermal exposure indirectly from the statistics of occupational skin diseases in 1975-2009.

Results: Inhalation exposure to most chemical agents had decreased. Using 1990 as the reference (100), the median values of P for 1950, 1970, 1990, 2008, and 2020 were 91, 149, 100, 58, and 41, respectively. The corresponding values were 218, 224, 100, 30, and 14 for P high, 151, 121, 100, 78, and 66 for L, and 119, 176, 100, 38, and 20 for NOIE. The trends varied considerably according to the agent. Exposure of, for example, asbestos, benzene, and benzo(a)pyrene substantially decreased. The annual incidence of occupational skin diseases due to chemical factors decreased from 6.9 per 10 000 employed in 1975-1979 to 4.6 per 10 000 in 2000-2009, suggesting a decrease in dermal exposure.

Conclusions: Inhalation exposure to most chemical agents has decreased in Finland since 1970. High exposures and the average level of exposure started to decrease already in the 1950s. The declining incidence of occupational skin diseases suggests that dermal exposure has also diminished. However, high exposures still exist and cause a substantial amount of occupational diseases and symptoms. Chemical exposures and the related disease burden are expected to continue decreasing in the future. These results cannot be generalized to other countries, particularly if the development phase of technology and the occupational structure of the labor force differ significantly from those in Finland.