A 2-year study has been carried out into the emissions produced during the processing of thermoplastic materials. One of the main reasons for the inception of the work was the perceived need by the plastics processing industry and material suppliers for data in order to comply with recent work-place legislation. Very few data obtained under 'real life' situations were available for consultation prior to the start of this study. The principal objective of the project therefore was to determine the effect that the processing of thermoplastics had on the workplace environment by the collection both of qualitative and of quantitative chemical data. During the study a wide range of bulk commercial thermoplastic materials were covered, including polyvinyl chloride (PVC), Nylon 6, acrylonitrile-butadiene-styrene (ABS), high impact polystyrene (HIPS), low density polyethylene (LDPE) and high density polyethylene (HDPE). In order to investigate the effect the type of process had on the emissions produced two principal fabrication methods were studied, namely injection moulding and extrusion-based processes. A wide range of species was detected in each process environment, it being possible to detect the relevant monomer(s) in some cases. However, none of the situations studied were found to generate a high level of process fume. The concentrations of the species detected were found to be in the range 0-2 mg m(-3) under standard processing conditions and up to similar to 10 mg m(-3) during purging operations. In none of the situations studied was any individual chemical species found at a concentration above the present occupational exposure limit. The data obtained shows that a higher level of fume is generated by extrusion-based processes than by those involving injection moulding. Emissions data were obtained both by personal exposure monitoring and from a number of static monitors positioned around the process equipment. This revealed the important effect that the monitoring position had on the data generated and the need to employ an effective sampling strategy if representative data was to be obtained. The results obtained also showed how the choice of sampling adsorbent could influence the data obtained. Tenax has been found to be a satisfactory general-purpose adsorbent material for this type of study.
