Bioaerosols alert: an occupational hazard
By Jak Fazakerley
Health experts are warning companies that deal with organic waste that they need to be more aware of, and act on, the potential occupational hazards associated with bioaerosols. A failure to ensure that all necessary health and safety precaution measures are implemented and maintained on-site could substitute neglect, thereby warranting further investigation from regulatory bodies, including HSE.
What are bioaerosols?
The term ‘bioaerosol’ is used to describe biologically active bacteria, fungi, viruses, molds and spores, or their products, that originate from water, soil, organic matter, animals and humans. Typically consisting of very fine particles measuring anywhere between 0.02 to 100 microns in diameter, bioaerosols are omnipresent and variable in time, duration of exposure, transmission, nature, space, chemical composition and concentration.
A variety of new industrial activities have emerged in recent years in which exposure to biological agents can be prevalent. Very often workers connected to organic waste transfer and treatment facilities (i.e. composting, anaerobic digestion and mechanical biological treatment) are continuously exposed to the conditions that excel the formation of bioaerosols, including loading and unloading, shredding, turning and screening. The degree of process control employed during these operations varies depending on the size and location of the site, the nature of the feedstock and the intended use of the end product.
Despite the benefits of organic waste management, there are concerns that occupational exposure to bioaerosols could be detrimental to health. Both the ingestion and inhalation of bioaerosols can lead to headaches, coughs, rashes, muscle aches, fatigue, gastrointestinal illness, eye irritation, dermatitis and cancer. Respiratory diseases, i.e. farmer’s lung, mushroom workers lung, asthma, chronic bronchitis, tuberculosis and pneumonia, are also common. Individuals with hypersensitivity pneumonitis or those with severely compromised or suppressed immune systems, e.g. following an organ transplant or if suffering from immune deficiency diseases, are at particular risk.
There are no occupational exposure limits (OELs) for biological agents, and for most of them, no dose-effect relationship can be determined due to different species, transmission routes, level of exposure and the complexities associated with human responses to different micro-organisms. Furthermore, cumulative exposure conditions may exist at workplaces.
Mitigation measures to combat occupational exposure
HSE’s document Health and Hazardous Substances in Waste and Recycling, Waste 27 (2012) and the Control of Substances Hazardous to Health Regulations (COSHH Regulations 2002) requires organisations to assess the risk from harmful substances and prevent or control exposure to them. This means that employers, such as waste management companies and local authorities, should follow the hierarchy of prevention, containment and protection so that workers’ exposure is adequately controlled so far as reasonably practicable.
Very often, the mitigation measures implemented to reduce occupational exposure to bioaerosols are based on a risk assessment, which identifies the hazard, assesses exposure, estimates the risk and characterises the risk so to establish the baseline.
The scope and level of detail will be site-specific. However, the implemented protocol or management plan should be both detailed and systemic, and incorporate a range of information dissemination, site design considerations, engineering controls and good working practices, including:
- providing induction and refresher training;
- providing communication channels for workers (if applicable);
- providing adequate personnel protective equipment (PPE), i.e. air-purifying filter respirators. Care must be taken that equipment is fitted and maintained in an appropriate manner;
- establishing risk-zone working practices;
- reviewing the design of production and storage systems;
- ensuring vehicle cabs are closed and have appropriate measures to encourage drivers to keep the windows closed, i.e. air conditioning;
- providing adequate welfare facilities;
- implementing health screening and monitoring to identify respiratory illness or sensitiveness;
- checking to ensure collection crews adopt good hygiene practices; and
- undertaking personnel monitoring to identify levels of bioaerosols within the workers exposure area.
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