California Artificial Stone and Silicosis (CASS) Project

Investigators: Kristin Cummings, MD, MPH, Robert Harrison, MD, MPH, and Amy Heinzerling, MD, MPH 

California workers who fabricate countertops using artificial stone are at risk of developing accelerated silicosis, a severe, incurable, and potentially fatal lung disease that is completely preventable. The Occupational Health Branch (OHB) of the California Department of Public Health (CDPH) has been instrumental in characterizing this emerging occupational health issue in California. We recently reported two fatal cases of silicosis in Hispanic immigrant countertop fabrication workers in their 30s and documented radiographic silicosis in 12% of their co-workers [Rose, Heinzerling, et al. MMWR 2019Heinzerling et al. AJRCCM 2021]. Investigation of the workplace revealed respirable crystalline silica exposures many times the permissible exposure limit, reflecting the much higher silica content of artificial stone compared to natural stone and the failure to implement well-established exposure controls for this hazard. 

The burden of silicosis in California’s countertop fabrication industry is unknown, but it is likely that these cases and the handful of others that have been reported to OHB represent the tip of the iceberg in an industry that employs at least 9,000 people statewide.  

The overarching aim of this project is to promote respiratory health among vulnerable workers in California’s countertop fabrication industry through education, medical monitoring, and statewide enhanced surveillance. The overall hypothesis of this project is that a multifaceted public health intervention will increase compliance with silica regulations and the detection of silicosis in the contemporary workplaces of California’s countertop fabrication industry. The specific aims are to: 

1. Increase awareness in the countertop fabrication industry about the risk of silicosis to workers using artificial stone and methods for effective strategies for prevention.  

As part of this aim, we will conduct outreach to employers and workers directly, and engage trade association, labor advocacy, and immigrant rights’ groups that represent the workers’ communities.  

2. Facilitate medical monitoring of silica-exposed workers in the countertop fabrication industry. 

This aim includes both promotion among employers and healthcare providers of currently mandated medical surveillance with chest radiography and spirometry, as well as support for the use of more sensitive radiological and functional diagnostic tools (low-dose computed tomography of the chest and diffusing capacity of the lung for carbon monoxide) on a pilot basis.  

3. Enhance public health surveillance of silicosis related to working with artificial stone through increased reporting.  
For this aim, we will establish a voluntary reporting system based on the public health authority of OHB to receive clinical data from healthcare providers, promote reporting to this system, and pursue addition of silicosis to the list of reportable non-communicable conditions in Title 17, California Code of Regulations. 

The working conditions in the countertop fabrication industry contributing to preventable lung disease reflect the larger economic trends in California that are the focus of the California Labor Lab. Small businesses, often owned by immigrants, employing an immigrant workforce, and dependent on episodic work and subcontractor relationships with other business entities, are poorly positioned for a solely regulatory approach to prevention. The addition of a public health approach could overcome these contemporary organizational challenges in this specific industry and serve as a model for health promotion in other California industries. 

Recruitment: The California Artificial Stone and Silicosis (CASS) Study is recruiting! Learn more below:

Related Links: