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New and Revised Limits Ensure Safety in the Workplace

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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.

A good many other substances that the Senate Commission has investigated are ones that we meet in daily life, and not just in the workplace. This applies to titanium dioxide, used in sun creams, to aluminium, which has applications as a light material and in electrical engineering, or dimethyl sulphurous oxide, which is used as a solvent and an anti-freeze. Thus the scientists – they work for the commission on an honorary basis and are completely independent – considered for example titanium dioxide together with two other substances to be candidates for the category "carcinogenic, but when used subject to the MAK and BAT Values, make no contribution towards the risk of cancer".

Before these values can be established however, further studies are necessary. For six substances – including dimethyl sulphurous oxide – the list specifies MAK Values, and in a further four cases the new studies confirmed the known value following careful consideration.

Aluminium and nine other substances received a new BAT Value, which in some cases takes account of the modified definition from 2007. In last year's list, for the first time average values were given as BAT Values, instead of maximum values.

In addition to the values cited, the scientists also examined whether a workplace substance causes cancer, modifies germ cells and therefore jeopardises reproduction, whether it can damage the unborn baby during pregnancy, is absorbed via the skin or sensitises the skin or respiratory tract. For example the fungicide thiabendazol changes germ cells, but the MAK value of 20 mg/m³ protects against this effect. The carcinogenic material cobalt and its compounds, as well as methoxyacetic acid, octyl tin compounds and pyridine, assessed this year as a suspected carcinogen, were assigned the warning label "H" given to substances which can be absorbed in dangerous quantities, also via the skin. For eight other substances, this classification was reviewed and maintained.

As is the case every year, after the submission to the Federal Ministry for Labour and Social Affairs, a time limit for objections applies to the current list. According to this, detailed written justifications for each assessed substance are requested to be sent to the Commission's Scientific Office by the end of the year, and any further new data and comments can be added, which are reviewed and taken into consideration where appropriate. Following this, the Senate Commission finally adopts the proposed values and their reasons as the basis for health and safety protection legislation in the workplace. Last year the Commission's Scientific Office received no comments on the new assessments.

Jutta Hoehn | Quelle: alphagalileo
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