Assessment of exposure to organic dust in a hemp processing plant

The aim of this preliminary study was to assess exposure to various constit uents of the organic dust generated during the processing of hemp in a smal l group of exposed workers. Airborne levels of inhalable dust, endotoxin an d soluble protein, and the respirable, thoracic and inhalable fractions of fungal, bacterial and actinomycete contamination were measured in the perso nal breathing zone of exposed workers. Inhalable dust, endotoxin, fungal an d bacterial contamination all exceeded levels found in similar vegetable fi bre processing factories, since inhalable dust levels ranged from 10.4 to 7 9.8 mg/m(3) and inhalable bacterial levels between 4.7 and 190x10(6) cfu/m( 3). Soluble protein and endotoxin (r=0.99, P<0.0001), endotoxin and inhalab le dust (r=0.94, P<0.005) and inhalable dust and protein (r=0.98, P<0.0001) were significantly correlated, suggesting that there was little variation in the composition of the dust from different sites or activities around th e workplace. Andersen sampling gave an indication of background microbe lev els, although no attempt was made to identify the specific microorganisms a s all plates were significantly overgrown. Airborne assessments demonstrate d that exposures were highly task specific. For example, sweeping the floor generated the highest exposure levels of total dust, protein, endotoxin, b acteria and fungi. Therefore, we have shown that a modern-day hemp fibre pr ocessing plant produces significant quantities of respirable dust which is highly contaminated with endotoxin and microorganisms. This organic dust ha s the potential to cause a range of ill health problems. Crown Copyright (C ) 2001 Published by Elsevier Science Ltd on behalf of British Occupational Hygiene Society. All rights reserved.