Crafting Safety: Mitigating Silica Exposure in the Engineered Stone Industry

Authored by AXA XL Casualty Risk Consultant, Workers Safety, Christina Roll

Engineered stone, commonly used in kitchen and bathroom countertops, is a sophisticated and multi-faceted material. It is a composite material made from crushed stone bound together by an adhesive, most commonly polymer resin. The manufacturing process results in a highly durable, non-porous surface, making engineered stone a popular choice for countertops and other applications.

The process of creating engineered stone begins with the selection of raw materials, which can include marble, quartz, granite, glass, or mirrors. These natural materials are crushed and combined with a resin binder under high pressure and heat, typically around 90°C (194°F). This mixture is then poured into molds to form slabs or shapes, which are then cured in kilns at a slightly lower temperature. The curing process enhances the strength and durability of the material. After curing, the slabs are calibrated for uniform thickness and then polished to achieve the desired finish.

A popular design choice

The ability to replicate the appearance of natural stone while offering a more uniform pattern and color is another advantage. The versatility in design and color, coupled with the material's resistance to stains and scratches, makes it a preferred choice for modern interior design. In fact, it’s getting even more popular. According to some market estimates, the Global Engineered Stone Market Size was valued at USD 23.7 Billion in 2022 is expected to USD 40.38 Billion by 2032.

Additionally, advancements in manufacturing technologies have allowed for a wider range of textures and finishes, further fueling the market's expansion. As environmental concerns and sustainability become more paramount, engineered stone is also gaining traction as an eco-friendlier alternative to natural stone, which involves more energy-intensive quarrying processes.

Lots of hands involved

Engineered stone touches a lot of hands, with many businesses and steps in its production and installation. Initially, suppliers of raw materials are pivotal, providing the essential quartz and resins. Manufacturing, the core of this industry, involves blending these materials to produce slabs that offer the beauty of natural stone with greater durability and lower maintenance.

Manufacturers work alongside designers and engineers to innovate in design, color, and finish, keeping pace with market trends and consumer demands. Distribution networks, including wholesalers and retailers, play a crucial role in making engineered stone available globally. Installation services, typically provided by specialized contractors, are essential for the correct application of engineered stone in various settings, including homes and commercial spaces.

A breathable health hazard

Despite its popularity, engineered stone poses several health hazards, especially during its production and processing. The primary risk involves the crystalline silica dust produced when cutting or grinding the material. Crystalline silica consists of small crystals with silicon and oxygen atoms. Although amorphous silica also consists of silicon and oxygen atoms, it is characterized by the absence of a crystalline structure and therefore does not pose a health risk.

Silica, a common component of engineered stone, is a natural mineral found in various materials and used in construction. However, its dust form poses health risks. Engineered stone, surprisingly, can have higher silica levels than natural stone, intensifying these risks. In fact, it may contain as much as 90–97 percent crystalline silica content. Granite contains only 10-45 percent silica content whereas marble has less than 5 percent.

Inhaling crystalline silica dust can lead to silicosis, a severe lung disease, and increase the risk of lung cancer and other respiratory illnesses, such as, chronic obstructive pulmonary disease (COPD), and even potentially chronic kidney disease. The amount of crystalline silica that workers can safely be exposed to is very small – OSHA’s Permissible Exposure Level (PEL) is 50 micrograms per cubic meter (µg/m3); and the Threshold Limit Value (TLV) set by the American Conference of Governmental Industrial Hygienists (ACGIH) is 25 µg/m3 – meaning companies could have a serious hazard in their workplace and not realize it.

There’s growing concern about silica exposure for workers involved in the manufacturing, distribution or installation of composite stone. In December 2023, California became the first state to take action to protect workers in the stone fabrication industry from silica exposure. The California Occupational Safety and Health Standards Board (OSHSB) approved an emergency temporary standard (ETS) for respirable crystalline silica. The emergency order was prompted by a “statewide epidemic of silicosis among engineered stone fabrication workers.”

In September 2023, OSHA issued a memorandum announcing a new initiative to conduct enhanced enforcement and compliance assistance efforts in the engineered stone fabrication and installation industries.

Setting safety procedures in stone

To enhance worker safety in the engineered stone industry, any business involved must prioritize a comprehensive approach to mitigate silica exposure. This approach encompasses several key strategies:

• Risk Assessment and Management: Companies must conduct thorough risk assessments to identify potential silica exposure points throughout the production, processing, and installation phases. This involves understanding the tasks that generate silica dust and the extent of exposure. A management plan should then be developed to address these risks.
• Engineering Controls: Implementing engineering controls is a primary method to reduce silica dust. This includes using equipment with built-in dust extraction, water spray systems during cutting and grinding, and proper ventilation systems to remove airborne silica particles. Enclosing processes and using air filtration systems can also be effective.
• Substitution of Materials: Whenever possible, businesses should explore the use of alternative materials with lower silica content. Although this may not always be feasible given the specific properties of engineered stone, partial substitutions or modifications in the manufacturing process can help reduce the overall silica content.
• Wet Methods and Work Practices: Implementing wet methods during cutting, grinding, and polishing reduces dust generation. This involves using water to dampen the stone and dust before it becomes airborne. Workers should also be trained in safe work practices to minimize dust generation and exposure.
• Personal Protective Equipment (PPE): Providing appropriate PPE, such as respirators, dust masks, goggles, and protective clothing, is essential. Workers should be trained on the correct use, maintenance, and disposal of PPE.
• Health Surveillance and Training: Regular health check-ups and monitoring for workers exposed to silica dust are crucial. This includes respiratory function tests and other relevant medical examinations. Training programs should educate workers about the risks of silica exposure, safe handling practices, and the use of protective equipment.
• Workplace Cleanliness and Maintenance: Regular cleaning and maintenance of the workplace help to reduce silica dust accumulation. This should be done using wet methods or vacuum systems with HEPA filters rather than dry sweeping, which can re-suspend silica particles into the air.
• Regulatory Compliance: Businesses must comply with local and national regulations regarding silica exposure, such as OSHA’s silica standard. This involves maintaining proper records, conducting exposure assessments, and implementing a written exposure control plan.
• Community and Worker Engagement: Engaging with workers and local communities to raise awareness about silica hazards and preventive measures is vital. This can be achieved through regular meetings, training sessions, and open communication channels.
• Innovation and Continuous Improvement: The industry should invest in research and development to innovate safer methods of working with engineered stone. This could involve developing new tools, processes, or materials that reduce silica exposure.

By implementing these strategies, businesses in the engineered stone industry can significantly reduce the health risks associated with silica exposure, ensuring a safer working environment for their employees.

To conclude, the health risks associated with silica exposure in engineered stone are significant. However, through awareness, engineering controls, protective equipment, and safe work practices, these risks can be substantially reduced. It's crucial for employers and workers to collaboratively ensure that safety measures are in place and strictly followed to protect health and well-being. Employing methods such as the wet method, which almost eliminates dust, and ensuring proper ventilation and PPE use, are key steps. Compliance with OSHA standards, including employee training and industrial hygiene testing, is also essential. Regular testing and monitoring of employees' health can further contribute to a safer working environment.