Abstract  In a painter's workshop, where 27 painters and 10 auxiliaries are employed, industrial hygiene and medical tests were performed in view to solve the question as to a relationship existing between the hydrocarbon solvents of high boiling point used in this workshop and the observed health damages. The results of these tests have shown that the painters have been working for several years mainly with a solvent composed of trimethylbenzene. The concentration of this solvent in the air varied between 10 and 60 ppm. Besides a survey of the general work conditions and of the sickness absenteism, the workers were submitted to a thorough medical examination. The latter revealed for the 27 painters a remarkably high percentage of subjective nervous complaints, bronchitis with asthma, anaemic hyperchromic blood picture, and coagulation troubles. These pathological states had to be put on account of the exposure to trimethylbenzene.

Abstract  The Ontario Ministry of the Environment (MOE) has identified the need to develop and/or update air quality standards for priority contaminants. The Ministry’s Standards Plan, which was released in October, 1996 and revised in November, 1999, identified candidate substances for which current air standards will be reviewed. Once all consultations have been completed, all substances will be incorporated into the Regulation as standards (as opposed to guidelines). 1,2,4-Trimethylbenzene (1,2,4-TMB) was identified as a high priority compound for review based on its pattern of use in Ontario and recent toxicological information that has been published. This document provides a review of scientific and technical information relevant to the setting of Ambient Air Quality Criteria (AAQC) and half-hour Point of Impingement (POI) standards for 1,2,4-TMB and other trimethylbenzene isomers.