Cleaning work involving petroleum containing benzene

Status:

completed 04/2003

Aims:

In the past, components were often cleaned with petrol containing benzene during maintenance and repair work, in particular in the machine construction sector and the automotive trade. TRGS 900, one of the technical rules governing hazardous substances, which governs atmospheric limit values at the workplace, classifies benzene as a carcinogenic hazardous substance. Diseases suffered by employees who had performed cleaning work using petrol containing benzene justify assumption of a causal connection between the disease and the exposure to benzene. The exposure data available to the German institutions for statutory accident insurance and prevention relating to detection of the occupational diseases in question, and based upon hazardous substance measurements performed at appropriate workplaces, are limited in their scope. For this reason, exposure assessments are often performed by analysis in such cases. This project involved the creation of a specific model work situation in which petrol containing benzene was employed as a cleaning agent. The benzene concentrations arising under the selected conditions were measured by a range of measuring systems. The concentrations measured by the instruments were compared with those determined by analysis for the purpose of validation of the analytical procedure.

Activities/Methods:

Cleaning operations involving the use of petrol containing benzene as a cleaning agent were simulated in a cabin suitable for modelling of a work procedure. The benzene concentrations arising were measured both by instruments providing a direct reading and by integrating measurement procedures. Standard commercial petrol (fuel for internal combustion petrol engines) enriched to a benzene content of approx. 6% was employed as the cleaning agent. Benzene levels of this magnitude were common in fuels in the past. During performance of the test, the individual performing the cleaning work was protected against exposure to benzene by protective overalls and external breathing apparatus. The benzene concentration values obtained by the measurements were compared with the values obtained by analysis as described in the BIA-Report 3/2001.

Results:

The tests demonstrated that the mean concentration of hazardous substances in the atmosphere could be determined with sufficient accuracy by means of the calculation method described in BIA Report 3/2001. The calculation model assumes that the hazardous substances are distributed homogeneously in the atmosphere concerned. In practice, however, the distribution is frequently inhomogeneous. In these cases, the calculation model allows for the introduction of a correction factor (local factor, LF) for measurment of the exposure. The local factor must be determined empirically for the working area concerned. Under the conditions stated, a local factor (LF) of 6 can be assumed, by which the concentration in the breathing area can be determined from the calculated concentration in the atmosphere.

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