New Swedish occupational standards for some organic solvents

Critical effects and exposure limits

The use of critical effects in the determination of occupational exposure limits (OELs) in Sweden is subjected to a statistical study. Many of the present OELs are high in relation to known no-effect levels and effect levels, and the degree of protection has a surprisingly weak correlation with the seriousness of the adverse effect. Several proposals for improved procedures are put forward. One of these is to supplement the concept of critical effects with that of dominant effects. A dominant effect of a substance is a health effect that is at some concentration the most serious health effect.

Irritation effects from experimental exposure to n-butyl acetate

The irritation produced by acute exposure to n-butyl acetate in human subjects without any history of occupational solvent exposure was studied in three experiments. Exposure levels tested in the different experiments were 350, 700, 1,050, and 1,400 mg/m3 in 20 min sessions, 70 and 1,400 mg/m3 in 20 min sessions, and 70 and 700 mg/m3 in 4 h sessions. Rating scales, various measures of eye irritation, and pulmonary functions were used to evaluate the irritation produced by the exposures in different parts of the study. The results indicate only very slight irritation from the exposures as revealed by categorical ratings, magnitude estimation, and some of the clinical measures of eye irritation and pulmonary functions, such as eye redness, lipid layer thickness, and bronchial responsiveness. These essentially negative results indicate the need to explore and develop the utility of new/different methods of quantifying irritative effects of exposure to various substances.