Confronting the Dangers of Engineered Stone

Surfaces of all kinds are top of mind these days, so we decided to look at all aspects of them, in these articles, from A to Z. Thinking of surfaces less as a product category and more as a framework, we use them as a lens for understanding the designed environment. Surfaces are sites of materials innovation, outlets for technology and science, and embodiments of standards around health and sustainability, as well as a medium for artists and researchers to explore political questions.

For designers, developers, and their clients, the biggest dilemmas involving countertops tend to be durability, looks, and cost. But for more than 2 million workers who handle raw materials for these ubiquitous surfaces before their installation, the greatest concern is health.

Commonly made of engineered stone by brands like Cambria, Silestone, and Caesarstone, the low-maintenance counters are safe to have and use once they’re installed. But the U.S. Department of Labor’s Occupational Safety and Health Administration (OSHA) has made renewed efforts to enforce long-ignored regulations of the production of surfaces made with quartz, which often contain high amounts of the natural mineral silica.

Engineered stone is a mix of ground natural stone and resin. Like much of the earth’s crust, natural stone contains crystalline silica, and when pulverized during fabrication or processing it becomes easy to inhale, or “respirable.” Exposure to respirable crystalline silica (RCS) causes inflammation and, over time, permanent lung scarring. This condition, known as silicosis, can lead to tuberculosis, lung cancer, chronic bronchitis, autoimmune disorders, and kidney disease, according to the American Lung Association.

Engineered quartz counters pose a higher risk than natural stone, because workers are exposed to dust that is more than 90 percent silica. By comparison granite may contain up to 50 percent, and some varieties of marble and limestone may contain no silica at all, according to data cited by OSHA. Workers in manufacturing—those opening bags of ground quartz or mixing raw materials—have a high risk of exposure to RCS. But those in quartz countertop fabrication who are cutting, sawing, grinding, and drilling into the material face risks as well.

Silicosis may be treated, but not cured, so the industry must prevent it. In 2016 OSHA introduced two respirable crystalline silica standards: one for general industry and maritime, which covers manufacturing; and another for construction, which covers finishing and installation.

Both standards lowered permissible exposure levels and require employers to implement control measures, such as water sprays or local exhaust ventilation, and to provide personal protective equipment. The regulation also makes employers responsible for training, hazard communication, record-keeping, and in some cases exposure measurement and medical surveillance.

Compliance with OSHA’s silica standards has been required since 2018, but in June 2020 the agency issued a new directive to establish uniform inspection and enforcement procedures. The document includes two checklists: one for general industry and one for construction. Anyone wanting a bird’s-eye view of the regulation and a tool for checking compliance need look no further than Appendix F of the new directive.

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