Notice of Intent to Sole Source: West Virginia University Research Corporation

Engineered stone countertops containing more than 90% crystalline silica have become increasingly popular among consumers in recent years. As a result, the rapidly growing workforce in this industry is at significant risk of a well-documented occupational hazard overexposure to respirable crystalline silica (RCS), which can lead to progressive, irreversible, and potentially disabling pulmonary silicosis. Epidemiological studies have also linked occupational exposure to RCS with the occurrence of autoimmune diseases, including lupus erythematosus, systemic sclerosis, and rheumatoid arthritis. However, the relationship between the development of these autoimmune diseases and silica-induced inflammation and fibrosis remains unclear, and the underlying mechanisms of RCS-induced autoimmune responses have not been fully elucidated. This study hypothesizes that dust from engineered stone fabrication may cause serious health issues, especially triggering autoimmune responses. To test this hypothesis, animal studies are required. This project involves oropharyngeal aspiration studies to evaluate autoimmune responses to chronic exposure to emissions from engineered stone materials in mice. The project was initiated at CDC/NIOSH/HELD in 2024 and paused in 2025. The overall objective of this project is to evaluate the immune responses to dust released from engineered stone countertops during fabrication processes in mice to better understand worker health risks associated with these exposures. This study will employ a sensitization and challenge model to evaluate autoimmune responses following repeated exposure to engineered stone dust. To determine engineered stone dust (ESD) induced autoimmune responses in mice, two strains of mice (NZBWF1/J and C57BL/6J) will be exposed to two ESD variants Silestone (~90% crystalline silica) and HybriQ (~60% crystalline silica) with evaluation at 90 days post-exposure. The study design will include two mouse strains, two ESD variants, and three exposure groups (Silestone, HybriQ, and PBS control), with 8 mice per group and a single exposure dose, followed by a 90-day post-exposure period. The total number of mice is 48 (24 NZBWF1/J and 24 C57BL/6J).