The occupational exposure limits describe the average concentration of a substance in the air at an average working time over a given reference period up to which no acute or chronically harmful effects on the health of employees are to be expected. The occupational exposure limit is defined and used in the ordinance on hazardous substances. A list of occupational exposure limits can be found in the technical rules for hazardous substances (TRGS) 900.

Sources: ordinance on hazardous substances, technical rules for hazardous substances 900