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EH&E’s Certified Industrial Hygienists (CIHs) possess the experience, knowledge, and expertise to conduct comprehensive assessments of exposure and ensure safe working environments. We can measure, evaluate, and reconstruct exposure levels of chemicals, dusts, and biological contaminants in almost any occupational environment using state-of-the-art scientifically validated sampling methodologies and analytical strategies. Based on these data, we quantitatively assess the risk and develop programs and recommendations to improve industrial hygiene, communicate hazards, and monitor employees and the area for future contamination. Our industrial hygienists also have worked on community exposures resulting from emissions from various industrial operations. Our CIHs approach problem-solving through a combination of scientific rigor and regulatory knowledge. EH&E’s industrial hygienists receive state-of-the-art training in new exposure assessment techniques and data analysis techniques including Bayesian Decision Analysis, censored data analysis, sampling strategy development, appropriate use of mathematical exposure models, industrial hygiene statistics and data interpretation. Our industrial hygienists prepare and review Material Safety Data Sheets for manufactures and distributors of products that contain hazardous chemicals.
This comprehensive industrial hygiene skill set provides clients with confidence when faced with challenges such as a compliance issue or what is “best practice” in a particular situation. These skills also provide clients with a means of proactively managing risk.
Occupational Exposure Reconstruction to Benzene
As the operation no longer existed and the solvents used today are different than the ones used during the timeframe of interest, mathematical exposure reconstruction was the only feasible method for estimating the worker’s exposure 30 years ago. Data on benzene concentrations in the solvents used at the time and common work practices were collected. The two zone exposure model, which establishes an area near the source as the “near zone” and the rest of the room as the “far zone”, was initially used in this project. A Monte Carlo analysis was conducted to evaluate the variability and uncertainty in model inputs. A Monte Carlo analysis allows model inputs to vary in a controlled manner within a defined range; the result of this analysis is a distribution of possible exposures that could arise with the particular model. The Monte Carlo output provided a range of possible exposures for the worker, e.g., 95% of the exposures were less than a particular value.
Investigation of a Large Occupational Illness Outbreak
More than fifty employees were experiencing a wide range of symptoms characterized by medical professionals as allergic reactions to an unknown agent. The affected employees worked in different areas of the plant with many different jobs ranging from purchasing agent to manufacturing technician. The challenge was to identify the source of the agent, establish the pathway to the workers, and ultimately design a control that works. To use the source-pathway-receptor model to solve this problem, the industrial hygienists needed to collect information on changes to the plant including ventilation, manufacturing processes, and work practices. Likely and unlikely source agents needed to be identified. This approach required analyzing many hundreds of potential chemicals to find candidates for further follow-up. Next, the pathway(s) needed to be identified that could account for the occurrence of disease in remote areas of the plant.
One pathway of exposure could have been entrainment of process emissions so mathematical modeling of stack emissions and potential for entrainment was conducted. In addition, a GIS approach was used to map locations, types of effects as well as date and time of disease recognition. Location mapping, combined with a prioritized list of sensitizers pointed to two locations in the plant as possible sources of several potent sensitizers. The industrial hygienists used surface sampling to establish the pathway to other areas of the plant. The soda machine, coffee machine, bathroom doors and desk surfaces in purchasing and human resources all showed clear contamination with aliphatic and aromatic amines. These amines were also found on worker hands, tables in the break areas, lunchrooms, gym and even the palm/fingerprint reader that was used to sign in and out of the plant. The results were clear; sensitizing chemicals were found that could account for the observed effects and the exposure pathway was established using objective data and measurements. The solution proposed to the plant was to thoroughly clean the plant surfaces that workers could come in contact with, to test the surfaces to ensure they are clean, and to train/educate the workers using the surface sampling data on methods to prevent the spread of these potent sensitizers outside their work area. EH&E worked with the plant management to communicate its findings to all employees. The result is that the allergic reactions were eliminated. To ensure the safety of the employees and at the recommendation of EH&E, the plant instituted regular surface sampling checks for migration of the sensitizers out of the manufacturing areas.
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