Crystalline Respirable Silica Exposures in a Clay Manufacturing Company; An Analysis of Health Risks and Prevention Strategies

Abstract

A study was conducted at XYZ Pottery Clay Manufacturing to analyze employees’ exposure to total respirable dust and respirable crystalline silica. Minnesota Occupational Safety and Health Administration (OSHA) collected air sampling data, as well as reviewed employee interview results; ventilation system analysis and respiratory protection program assessment information were also assessed. The relevant information was accessed through the Freedom of Information Act (FOIA) and an application submitted to MN OSHA. Based on the personal air sampling results for four employees who were involved in clay mixing, it was found that their exposure to respirable dust was below the 8-hour time-weighted average (TWA) permissible exposure limit (PEL) of five milligrams per cubic meter (mg/m3). However, the head mixer and the pug mill operator were found to have experienced respirable crystalline silica exposures above the MN OSHA PEL of 50 μg/m3 for an 8-hour work shift. The information gathered from employee interviews indicated that the facility's ventilation system is ineffective and that there is a lack of a comprehensive respiratory protection program. Based on the employee exposure as well as ventilation and respiratory protection program deficiencies, it was recommended that XYZ Pottery Clay Manufacturing reevaluate its engineering as well as administrative silica exposure controls, including an upgrade to the existing exhaust ventilation, improving the general ventilation system, developing a comprehensive right-to-know program, monitoring worker exposure to respirable dust and respirable crystalline silica, and developing a comprehensive respiratory protection program that includes fit-testing and medical evaluations for workers who are required to wear respiratory protection for airborne crystalline silica.