New and revised limits ensure safety in the workplace

Along with its MAK and BAT Values, in 2008 the DFG presents so-called BAR Values for the first time

The Senate Commission for the Investigation of Health Hazards of Chemical Compounds of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) submitted the annual list of MAK and BAT Values to the Federal Ministry for Labour and Social Affairs at the beginning of July. These constitute the set of recommendations for health protection in the workplace, proposed following careful scientific examination. 60 changes and additions to the current list are proposed, with its maximum concentrations of substances in the air that do not have an impact on health (MAK Values), and the concentration of a substance in the body that a human being can be exposed to over a lifetime without suffering damage to health (BAT Values). For the first time, this year's recommendations also include the so-called Biological Substance Reference Values (Biologische Arbeitsstoff-Referenzwerte, BAR Values). These are not limits, but they define the "background exposure" of a substance in the body – as measurable in the blood, for example. It therefore refers to the exposure of adults of working age who are not exposed to the substance in the course of their work. The comparison – for example during biomonitoring in factories – of this "background exposure" with the measured exposure at the workplace reveals whether, or to what extent, a person has absorbed a substance through their work. This is particularly important for carcinogenic substances, for which no limit has previously been derivable that protects against damaging effects with any certainty. The first BAR Values proposed by the Commission are for chromium and its inorganic compounds, materials known to be carcinogenic, as well as for trinitrotoluene – also known as the explosive TNT.

In contrast to the BAR Values, the objective of the MAK Values is to establish a scientifically grounded value that will definitely protect against the negative effects of particular substances. Even here, in many cases a comparison is involved – as in the case of isoprene, which this year has been given an MAK Value. This is because the naturally occurring substance, even being produced in the human body, which as a component of many biomolecules in the body is very useful for natural substances such as rubber and for many aromatic compounds in industry, is known to be a carcinogen and is able to modify germ cells. Following a comparison with the so-called endogenous concentration however, i.e. that formed as part of the body's metabolism, the commission has established that at an MAK Value of 3 ml/m³ working with this substance does not increase the naturally occurring risk.