[Levels of exposure to respirable fibres at worksites for abatement of compact and friable asbestos].

BACKGROUND

Starting from a project aimed at assessing the carcinogenic risk in some industrial sectors covered by Local Health Authority No.1 (LHA) in Perugia (USL Umbria1, Italian acronym), worksites for abatement of materials containing asbestos (MCA) were examined in order to estimate respirable fibres exposure levels in workers. Abatement work is, indeed, a fast developing sector, but is not free from asbestos risks in the long-term, particularly carcinogenic risks; this kind of work therefore requires maximum effort in respecting prevention standards prescribed in the relative legislation.

OBJECTIVES

The aim of the research was to define the personal levels of exposure to respirable fibres and to create a reliable database for the interpretation of possible asbestos-related cases of neoplasms that may occur in the future in workers of this important occupational sector.

METHODS

The authors took in consideration operations both on compact MCA and on friable MCA. In the case of compact MCA, exposure values measured by the LHA via their own sampling were compared to those measured by the companies involved in the project. In the case of friable MCA, however, sampling was only performed by the LHA and the assessment covered not only workers' exposure levels but also the pollution levels in the areas in the vicinity of the work site.

RESULTS

In the case of compact MCA, results showed moderate average values of personal fibre exposure, and always considerably lower than the limit values (100 fibres/litre) prescribed by law (Legislative Decree 81/08); however, the average values detected by the LHA (15,8 fibres/litre) were significantly higher (p < 0.001) than those detected by companies (4,9 fibres/litre). In the case of friable MCA, however, average personal exposure values of workers (106,8 fibres/litre) were even higher than the limit values prescribed by current regulations, while in areas near the work sites, average fibre pollution levels (1,04 fibres/litre) were always very low and lacked significant variations (p > 0.05) during the different phases of work.

CONCLUSIONS

According to the authors, the data collected show how in MCA abatement operations a carcinogenic risk in the long-term is in any case present, and this both in compact MCA work, where not all the prevention measures were accurately observed, and even more so, in friable MCA work, where average exposure levels of workers showed a heavy trend to exceed the above mentioned limit values. Considering the different evolution of the results of sampling carried out by the LHA and by the companies, the authors also highlight the need to provide mandatory technical guidelines for industrial hygiene laboratories so that sampling and analysis methods are as homogeneous as possible, thus making the results of research easily comparable.