2.1.3. ACGIH®

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Adverse effects on health cannot be deduced from the exceedance by one single measurement. This is not valid for acute toxicity, which must not be permitted at any time. The individual evaluations of substances include evidence of acute toxic effects. Substances with a BAT* value that targets an acute toxic effect are marked with an appropriate footnote in the List of MAK* and BAT* Values (“derivation of the BAT* value as ceiling value because of acute toxic effects”).

Adherence to the BAT* values does not always guarantee the safe protection of the unborn child, as there are no or insufficient studies available on the harmful effects of many harmful substances on the health of the child. The MAK Commission* examines all harmful working materials with MAK* or BAT* values to determine whether a harmful effect is unlikely to occur, these are indicated by specific pregnancy groups. In the case of carcinogenic substances, the internal exposure must be assessed on the basis of the exposure equivalents for carcinogenic agents (EKA). Carcinogen categories and grouping categories of the MAK commission; for details refer to (DFG, 2021).

BLW*s are derived from non-carcinogenic effects of carcinogenic substances and for substances without sufficient data. They are likewise established as averages. If the BLW* is exceeded, the risk of health impairment cannot be excluded. Therefore, it is necessary to broaden the knowledge of the basics of the relationship between external and internal exposure and the resulting health risks in order to be able to derive BAT* values. In this context, BLW* are helpful in that they provide an important basis for the physician to be able to use biomonitoring at all. By continuous improvement of the technical conditions and the technical, hygienic and organizational protective measures, concentrations that are as far as possible below the BLW* should be aimed for. BAR* values describe the background level of a substance that is present concurrently at a particular time in a reference population of persons of working age who are not occupationally exposed to the substance. The BAR* values are based on the 95th percentile of the distribution function in a random sample from a defined population group. It must be taken into account that the reference level of the background exposure can be influenced by such factors as age, sex, social status, residential environment, lifestyle and geographical region. Occupational exposure in the individual or a group of workers can be identified by comparing the biomonitoring values with the BAR*.

2.1.3. ACGIH®*

The American Conference of Governmental Industrial Hygienists is a not-for-profit corporation and a professional association of industrial hygienists and practitioners of related professions with headquarters in Cincinnati, Ohio, USA. One of its goals is to advance worker protection by providing timely, objective, scientific information to occupational and environmental health professionals.

ACGIH®* establishes Threshold Limit Values (TLV®*s) for chemical substances and physical agents and Biological Exposure Indices (BEI®s*). Today, the list of TLV®*s and BEI®s* includes over 600 chemical substances and physical agents, as well as over 30 BEI®s* for selected chemicals (ACGIH, 2021).

BEI®s* are developed by committee consensus through an analysis and evaluation process. The detailed scientific criteria and justification for each BEI®* can be found in the Documentation of the Threshold Limit Values and Biological Exposure Indices. The principal material evaluated by the

BEI®* Committee includes peer-reviewed published data taken from the workplace (i.e., field studies), data from controlled exposure studies, and from appropriate toxicokinetic modeling when available. The results of animal research are also considered when relevant. The Documentation provides essential background information and the scientific reasoning used in establishing each BEI®*. In recommending a BEI®*, ACGIH®* considers whether published data are of reasonable quality and may also consider unpublished data if a complete copy of the data/report is provided to ACGIH®*, although unpublished data are never used as the primary basis for a BEI®*.

OCCUPATIONAL BIOMONITORING GUIDANCE DOCUMENT © OECD 2022