California Quartz Ban: Covered Materials, Reasons, and Key Dates

California’s “quartz ban” is not a ban on quartz countertops. It is a workplace safety regulation that prohibits dry cutting, grinding, polishing, drilling, and similar dust-generating methods when fabrication shops work with engineered stone and high-silica natural stone. The rule, in California Code of Regulations Title 8, Section 5204, targets how the material is cut and finished, not whether it can be sold or installed. Senate Bill 20, signed in October 2025, adds statutory weight and new training and reporting duties. If you already have engineered stone countertops in your kitchen, they are safe.¹

What Is Actually Banned

The core prohibition is simple. Employers cannot use any dry method when performing what the regulation calls “high-exposure trigger tasks” on covered stone. That means no dry cutting, grinding, drilling, polishing, chiseling, or breaking of engineered stone. Senate Bill 20 writes this prohibition into statute.²

The regulation also bans several related shop practices:

Using compressed air to blow dust off surfaces, clothing, equipment, or filters.
Dry sweeping or shoveling silica-containing dust and debris.
Walking or driving through accumulated dry dust.
Rotating employees through high-exposure tasks to spread out individual exposure.

These prohibitions apply regardless of measured air levels. Even when monitoring shows silica below the legal limit, the dry-method ban still applies to every high-exposure trigger task.¹

Which Countertop Materials Are Covered

The rule draws different lines for manufactured and natural stone.

Artificial stone, which covers any reconstituted, synthetic, composite, engineered, or manufactured stone product, is covered when it contains more than 0.1% crystalline silica by weight. That threshold is extremely low. Most engineered stone products on the market contain 90% or more crystalline silica, so essentially every quartz countertop is covered.³

Natural stone is covered when it contains more than 10% crystalline silica by weight. Granite falls in. Marble, which usually contains less than 5% silica, generally does not.¹

Can You Still Buy Quartz Countertops in California?

Yes. The regulation controls fabrication methods, not sales or installation. Shops that use wet methods, provide the required respiratory protection, and meet monitoring obligations can continue producing quartz countertops, and installers can continue putting them in.

Expect some practical effects, though. Compliance costs for fabrication shops have gone up. Smaller operations that cannot afford the equipment upgrades may stop working with engineered stone or close. Lead times may be longer and prices may be higher than before the regulation. Some buyers are moving to alternatives such as marble, porcelain, or solid-surface materials that sit below the trigger thresholds.

Are Existing Engineered Stone Countertops Safe?

Yes. Silicosis is caused by inhaling the fine dust released when stone is cut, ground, or polished. A finished, installed countertop in your kitchen does not release silica dust under normal use. The health risk is to workers in fabrication shops, not to homeowners living with the finished product.

Why California Enacted the Rule

Cutting and grinding engineered stone releases respirable crystalline silica. Inhaling it causes silicosis, a progressive and incurable lung disease that scars the lungs and can require a transplant or lead to death. The disease is centuries old in mining and construction, but the rise of engineered stone countertops in the 2000s produced a new wave of cases concentrated among young fabrication workers.

California has tracked engineered stone silicosis since 2019. By early 2024, the state had confirmed 296 cases tied to engineered stone fabrication, with at least 15 deaths and 60 referrals for lung transplant.⁴ By early 2026, the California Department of Public Health reported over 500 confirmed cases and at least 29 deaths. Many affected workers are in their 30s and 40s, far younger than the typical silicosis patient from other industries.

The federal permissible exposure limit for respirable crystalline silica is 50 micrograms per cubic meter as an 8-hour average, with an action level of 25 micrograms.⁵ California’s rule goes beyond that standard by imposing specific prohibitions and engineering controls for stone fabrication, rather than relying on exposure numbers alone.

What Fabrication Shops Must Do Instead

Since dry methods are banned, shops have to use wet methods for every high-exposure trigger task. The regulation accepts three approaches:

Running water, meaning a continuous flow applied directly to the contact area between tool and stone. Where water flow is built into the tool, flow rates must meet or exceed the manufacturer’s specifications. Recycled water must be filtered to remove silica before reuse.
Submersion of the work piece during fabrication.
Water jet cutting.

Dust must stay below the action level at all times. Wet methods alone are not enough: for high-exposure trigger tasks, employers must also provide respiratory protection. The default is a full-face, tight-fitting powered air-purifying respirator or an equally protective alternative. Shops must also keep a written exposure control plan and conduct periodic air monitoring, and must provide no-cost medical exams, including chest X-rays and pulmonary function tests, to workers who perform these tasks at least 30 days per year.¹

Key Dates

California’s response came in stages. The Cal/OSHA Standards Board approved an Emergency Temporary Standard on December 14, 2023, and it took effect on December 29, 2023.⁶ The Board voted to make the rules permanent on December 19, 2024, and the Office of Administrative Law filed the permanent standard on February 5, 2025, with immediate effect.¹

Governor Newsom signed Senate Bill 20 on October 14, 2025. Beginning July 1, 2026, employers performing high-exposure trigger tasks must submit an annual written attestation to Cal/OSHA confirming that every worker doing this work has received the required training. The law also directs the California Department of Public Health to conduct outreach on silicosis prevention and diagnosis.⁷ Senate Bill 20 also classifies silicosis from artificial stone as a “serious injury or illness” under the Labor Code, which tightens reporting timelines when a worker is diagnosed.²

1
Department of Industrial Relations. California Code of Regulations Title 8 5204 – Occupational Exposures to Respirable Crystalline Silica
2
California State Senate. Governor Newsom Signs SB 20 The Silicosis Training, Outreach and Prevention STOP Act
3
Centers for Disease Control and Prevention. Silica Hazards from Engineered Stone Countertops
4
US House of Representatives. Silicosis Surveillance in California, 2019-2024 – Tracking an Epidemic
5
Occupational Safety and Health Administration. Silica, Crystalline
6
California Department of Industrial Relations. Division of Occupational Safety and Health – Emergency Temporary Silica Standard – What Employers Need to Know
7
California Legislative Information. SB 20 – Senate Bill 20