Exposure to chemical and biological hazards poses a significant risk to workers. As such, it is imperative to recognize and anticipate these hazards as the major step towards instituting measures of reducing the risk through controlling exposure to chemical and biological hazards. Nevertheless, it is important to evaluate each of the hazards individually as it provides the key to understanding the threat posed by each. The risk evaluation process enables the industrial hygienist to make suitable recommendations on workplace controls while giving priority to chemical and biological hazards. Furthermore, evaluation is also the major technique used in determining adherence to the occupational exposure limits (OELs).
To begin with, focus is on chemical hazards. The first step in risk evaluation involves the identification of the chemical hazards. This may require reference to the chemical inventory within the facility. When documenting all possible chemical hazards, it is important to have a comprehensive approach. While paying attention to the use of chemical agents, the evaluation needs to look into chemical substances produced as a by-products of a process. For instance respirable crystalline silica and welding fumes are chemical hazards that arise from different process in a facility. Other aspects have to be considered such as chemical spillage or leaks that pose a hazard to the workers. Owing to the massive potential of inhalation exposure, it is necessary to perform air monitoring as well as surface sampling.
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Guidelines from OSHA provide employers with the option of modeling to evaluate the exposures or air sampling. Nevertheless the modeling approach comes with different complications hence not extensively applied in practice. As such, evaluating chemical exposures may require choosing between continuous monitoring methods and grab sampling methods. Grab sampling basically provides an estimation of the possible chemical exposure for a short-term period. In conducting grab sampling, the grab is obtained for a short period ranging from a few minutes to an hour ( Centers for Disease Control and Prevention, 2003) . It accurately measures the air concentrations during a specific process or task. On the other hand, continuous monitoring offers a time-weighted average (TWA) indicating the intensity of the chemical hazard. It involves obtaining a sample of air through a collection device for an extended period of time. For both grab sampling and continuous sampling, direct read meters and sampling tubes especially colorimetric tubes apply for the collection of samples. Currently, different direct read meters exist for use in the detection of chemical hazards in the air samples. Such meters provide accurate readings on the hazard being evaluated but only a small number of chemical hazards have meter sensors.
An important determining factor is chemical toxicity of and influences the type of sample for collection in the evaluation process. In this regard, chemicals with high acute toxicity require grab sampling methods due to their short-term exposure limit (STEL). On the other hand, chemicals with limited acute toxicity as well as those with chronic health consequences require the use of time-weighted average (TWA) and continuous sampling methods. Additionally, area and personal sampling with laboratory analysis applies in the evaluation of chemical hazards. It is worth noting that the accuracy of air sampling data depends on the sampling and methods of analysis used. OSHA guidelines demand an overall error of below 15%. Most importantly, only validated methods may be used for sampling and analysis of chemical and biological hazards as documented by the National Institute for Occupational Safety and Health (NIOSH) and OSHA.
Similarly, biological hazards are of equal concern in a workplace although normally more challenging to evaluate than chemical hazards. Numerous and varied biological hazards may arise from workplace exposure to organisms that pose threats human health. Even though employees in health and agricultural occupations face elevated risk of exposure to biological hazards, all places of work harbor the possibility for different forms of exposure to biological hazards, including worker-to-worker transmission of contagious infection.
Due to the nature of biological hazards, the main method of sampling biological hazards is personal sampling. A good example involves sampling aerosolized influenza. It required equipping the participants with a pack enclosing two aerosol samplers, the personal high-flow inhalable sampler head (PHISH) and the NIOSH bio aerosol sampler. It also incorporated two air pumps. The PHISH and the NIOSH bio aerosol sampler were standardized to specific air flow rates. The PHISH, being a recently designed sampler makes use of “standard 37 mm filter material” to accumulate aerosols in the inhalation zone at a rate of flow higher than other inhalable samplers (O’Brien & Nonnenmann, 2016). The PTFE filter of 37-mm, 0.3 μm pore size applies since it is suggested for sampling virus aerosols. Typically, this procedure requires a duration of half to one hour to obtain the sample for analysis. Afterwards, various laboratory analysis techniques apply in analyzing the samples to determine the biological hazards present. Examples of laboratory procedures include isolation of Viral RNA and quantitative immediate Polymerase Chain Reaction (PCR). This procedure enables the determination of the existence of different microorganisms. Especially those that pose threats to human health at the workplace.
In conclusion, both chemical and biological hazards present in almost all workplaces. Although some areas may contain higher levels of these hazards, it is nevertheless important to conduct evaluations so as to institute control, measures. While various methods exist for sampling chemical hazards, few are documented for evaluating biological hazards.
References
Centers for Disease Control and Prevention. (2003). Volatile organic compounds screening . Retrieved from: https://www.cdc.gov/niosh/docs/2003-154/pdfs/2549.pdf
O’Brien, K. M., & Nonnenmann, M. W. (2016). Airborne influenza A is detected in the personal breathing zone of swine veterinarians. PloS one, 11(2), e0149083.
Occupational Safety and Health Administration. (2013). Sampling, Measurements Methods and Instruments . Retrieved from https://www.google.com/url?sa=t&source=web&rct=j&url=http://osha.oregon.gov/OSHARules/technialmanual/Section2Chapter1.pdf&ved=2ahUKEwiF2MvA5NjbAhUCVRQKHX2TBGsQFjAAegQIAhAB&usg=AOvVaw0_fVc30LSrFMqiDNM_ziBX
