Direct Answer: The rule is not adopted yet, but October 2026 edits would extend the proposed artificial stone prohibition beyond countertops to bathroom surfaces, fireplaces, and flooring. Natural stone and porcelain classification is still unsettled.
You picked a slab for the kitchen counter. Then the same material showed up on the shower walls, the fireplace surround, and maybe a run of floor. That whole-house plan is where California’s proposed artificial stone rule got more complicated in October 2026.
In October the Cal/OSHA Standards Board edited the draft so the proposed prohibition would reach past countertops to surfaces including bathrooms, fireplaces, and flooring. Nothing has been adopted. Reporting indicates adoption could come as early as November 2026.
Most homeowners on the Monterey Peninsula are still treating this as a countertop question. It is a whole project question now, and the two surfaces people forget are the shower wall and the fireplace.
Does the California quartz ban include shower walls, flooring, and porcelain?
Here is the sequence, with dates, because the dates are what decide whether this touches your project.
- May 2026: workers testified at a hearing, and the board then voted 3-0 in favor of a ban on artificial stone.
- September 2026: a draft of the proposal was released.
- October 2026: the board made edits to clarify that it would extend beyond countertops to surfaces including bathrooms, fireplaces, and flooring.
- October 15, 2026: the Natural Stone Institute submitted public comments urging the board to revise the standard.
- Possible adoption: as early as November 2026, per Green Building Advisor’s reporting on the proposal.
The October edits also added language covering “any alteration that removes material from the slab beyond that necessary for a minor fit adjustment.”
That phrase is the part a Carmel-by-the-Sea remodel should pay attention to. A shower panel cut down to a 36 inch opening, a mitered fireplace return, a floor perimeter scribed to an old wall: none of those are minor fit adjustments. They are cuts, and cuts are what the draft language addresses.
The part that lands on your fabricator, not on your slab
A question comes in on the phone almost every week: do you cut and install? Showrooms like ours supply material. Your fabricator cuts it and your installer sets it. Those are separate businesses, and the proposed rule is a workplace safety standard, so it reaches the shop doing the cutting.
That split matters for timing. If your spec calls for an artificial stone slab on three bathroom walls, the person who needs to answer “can you still cut this, and when” is your fabricator, not your designer.
Two practical things to do this month:
- Ask your fabricator directly what material categories they plan to keep cutting if the standard is adopted, and get the answer in writing on the quote.
- Make a surface list before you buy. Counters, island, backsplash, shower walls, tub deck, fireplace, floor, thresholds. One list, every surface.
- Sequence it with your permit. On the Monterey Peninsula, coastal and design review timelines already stretch the front end of a remodel, so material decisions made late have the least room to move.
For more on that sequencing problem, we wrote about stone selection and permit timing earlier this year.
Surface by surface: what the October edits ask you to check
Use this as a working checklist with your fabricator. The final adopted text has not been published, so treat every row as a question to confirm, not a conclusion.
| Surface in your project | Common plan | What to confirm now |
|---|---|---|
| Kitchen countertop and island | Slab, 2 cm or 3 cm | Countertops were in scope from the September draft. Confirm the material category with your fabricator. |
| Shower walls and tub surround | Slab panels cut to size | October edits name bathroom surfaces. Cutting panels to an opening goes past a minor fit adjustment. |
| Fireplace surround and hearth | Matching slab, often mitered | Named in the October edits. Miters and returns remove material from the slab. |
| Flooring | Slab or large-format tile | Named in the October edits. Perimeter cuts and thresholds are cuts, not fit adjustments. |
| Natural stone and porcelain | Marble, quartzite, granite, porcelain slabs | NSI asked the board on October 15, 2026 to distinguish these from engineered stone. The board has not adopted final language. |
How the proposal got here
A short timeline of the Cal/OSHA artificial stone proposal through fall 2026, with the dates that matter to an active remodel.
Where natural stone and porcelain sit while this plays out
This is the question designers in Palo Alto and Carmel keep raising, and the honest answer is that it is still open.
In its October 15, 2026 public comments, the Natural Stone Institute asked the board to incorporate clearer, science-based exposure limits that would better protect workers and distinguish engineered stone from natural stone. The group also asked Cal/OSHA to state plainly that natural stone and fired ceramic or porcelain slabs, tiles and panels are not regulated as artificial stone. That is a request, not an adopted outcome.
One naming issue causes real confusion on the phone. Quartzite is a natural stone, quarried and cut, and it is not the same product category as quartz. People shopping Taj Mahal, Naica, or a leathered blue quartzite are shopping natural stone, and the difference between two lookalike quartzites is covered in our piece on Naica versus Taj Mahal quartzite.
If your spec calls for a silica free quartz slab, that is a separate product line with its own documentation. We only carry crystalline silica-free quartz, and what that term covers is explained in what crystalline silica-free quartz actually means for your kitchen. The team can share product documentation for any slab you are considering.
What a Central Coast remodel should do in the next 30 days
Material changes get expensive the later they happen. Costs vary by project, but a change made before selection is final generally costs far less than one made after your fabricator has templated and started cutting, because templating, delivery, and restocking all get repeated.
A workable order of operations:
- List every surface in the spec that calls for a slab, including the ones nobody photographs.
- Ask your fabricator which categories they will keep cutting and what their current lead time looks like.
- Pull samples home. Carmel light and Pebble Beach light are not showroom light, and take-home samples settle arguments fast.
- Look at the actual slab. Natural stone varies block to block, so a catalog image is not a decision.
- Keep a backup selection in the same color family for any surface where the rule’s final wording could change your plan.
Shower walls deserve their own conversation regardless of the rule, since panel size, substrate, and setting method drive the install. We covered that in large-format stone tile in showers.
And if you want the background on how the fabrication rules got written in the first place, start with what California’s quartz fabrication rules mean for your countertop choice.
Frequently Asked Questions About the Proposed Rule and Your Project
Is the rule in effect right now?
No. As of this writing the standard has not been adopted. The board voted in favor of a ban in May 2026, released a draft in September, and made edits in October. Reporting indicates adoption could come as early as November 2026.
Does this affect the quartzite slab I already put on hold?
Quartzite is a natural stone, not quartz, so it sits in a different product category than artificial stone. The Natural Stone Institute asked Cal/OSHA on October 15, 2026 to say plainly that natural stone is not regulated as artificial stone, and the board has not adopted final language yet. Your fabricator is the right person to confirm their own plans.
What about porcelain slabs on a shower wall?
Fired ceramic and porcelain were part of the same clarification request submitted in October. Nothing is settled. Porcelain also carries its own fabrication demands around edge work, which is worth raising with your shop separately from any regulatory question.
Do you cut and install the slabs you sell?
No. We are a supplier and showroom with live inventory across Carmel, Palo Alto, and Sand City. You work with your own fabricator or installer, and the team can share referrals if you need one.
Can I still get silica free quartz for my kitchen?
We carry crystalline silica-free quartz and can share product documentation for any slab you are looking at. For current availability in a specific size and finish, the team will confirm, since live inventory changes with incoming shipments.
Looking at slabs for more than just the countertop?
If your Carmel, CA project puts the same material on the counter, the shower wall, and the hearth, it helps to see the actual slabs together before anything is ordered. Carmel Stone Imports keeps live inventory at the Carmel, Palo Alto, and Sand City showrooms, with take-home samples for most materials. Slab selection appointments can be arranged at (650) 800-7840 or info@carmelimports.com, and the team will confirm what is on the floor.
