General occupational data · OSHA
100×
smaller than ordinary sand — that's respirable crystalline silica.
The particles that damage lungs are far too small to see. They stay airborne for hours and reach deep into the lungs, which is why "I don't see dust" is not a safety plan.
General industry · OSHA 29 CFR 1910.1053
50 µg/m³
is OSHA's legal limit for respirable silica over an 8-hour day — and the action level is just 25 µg/m³.
The standard covers ceramics manufacturing. The limits are measured in micrograms — millionths of a gram. Ordinary dry sweeping and mixing can exceed them fast.
Source: OSHA final rule, Occupational Exposure to Respirable Crystalline Silica
General occupational data · OSHA
2.3M
U.S. workers are exposed to respirable crystalline silica on the job.
Silica exposure is one of the most common serious workplace hazards in the country. Potters — including home-studio potters mixing dry clay and glaze — are part of that exposed population.
General occupational data · IARC
Group 1
carcinogen: crystalline silica inhaled as quartz or cristobalite is "carcinogenic to humans."
That's the same classification as asbestos and tobacco smoke. Beyond cancer, OSHA links silica to silicosis — an incurable lung disease that can lead to disability and death — plus COPD and kidney disease.
Pottery-specific · NIOSH & NJ Dept. of Health
47%
of personal breathing-zone samples in a New Jersey pottery plant exceeded OSHA's silica limit; 53% exceeded NIOSH's recommended limit.
Chest X-rays of the plant's 120 workers found 5 people (4%) with previously undetected lung scarring consistent with pneumoconiosis. This was a commercial pottery — but the dust sources (dry materials, mixing, poor ventilation) are the same ones in home studios.
Source: CDC MMWR — Silicosis Among Pottery Workers, New Jersey
Pottery-shop-specific · NIOSH
40×
the recommended limit: NIOSH measured short-term silica spikes of 2.0 mg/m³ during clay mixing at a working pottery shop — against a full-shift limit of 0.05 mg/m³.
True scale. One employee's full-shift exposure at this shop was right at the NIOSH limit even with respirators in use.
Source: NIOSH Health Hazard Evaluation Report 2007-0127-3068, pottery shop, Cincinnati OH
Ceramics-specific · CDC
53 µg/dL
was the highest blood lead level in a family of five poisoned by lead leaching from traditional glazed ceramic ware.
Blood lead levels in the family (µg/dL):
The glaze measured 15.7 mg of lead per cm². Levels fell once the family stopped using the ware.
CDC also notes that homemade or craft pottery "can release large quantities of lead, particularly if the glaze is chipped, cracked, or improperly applied." If you sell functional ware, glaze food-safety testing isn't optional.
Sources: CDC MMWR — Lead Poisoning from Glazed Ceramic Ware, NYC 2017–2022 · CDC MMWR — Lead Poisoning from a Ceramic Jug
Kiln incident · JEMS
30
students hospitalized after fumes from a small kiln fire at a Chicago-area school.
Kiln firings release carbon monoxide, sulfur oxides, and other gases; the Ceramic Arts Network calls carbon monoxide in kiln fumes "the most immediate hazard." A kiln in a closed garage or basement without dedicated venting can fill the room fast.
Sources: JEMS — 30 Students Affected by Kiln Fumes · Ceramic Arts Network — Kiln Venting
Engineered stone fabrication · California DIR / Cal/OSHA
31 → 631
silicosis cases among California's engineered-stone workers — 31 in 2019, 631 by mid-August 2026.
Silicosis is incurable, and it comes from crystalline silica — the same mineral in pottery clay bodies and dry glazes. 35 workers have died and 58 have needed lung transplants since 2022. On September 16, 2026, California published a draft emergency rule to ban manufactured stone containing more than 1% crystalline silica.
Sources: NY Post — California moves to ban engineered stone (Oct 6, 2026) · IQAir — California aims to ban artificial stone countertops
What this means for your studio
These numbers describe studied workplaces — not a prediction about your studio. But the hazards are the same ones in a home studio: dry clay and glaze mixing, an unvented kiln, untested foodware glazes. The fixes are ordinary and affordable: wet methods, ventilation, respirators used correctly, and knowing what's in your materials.
That's exactly what the assessment walks you through.
Sources
- OSHA — Silica, Crystalline — Overview (particle size, 2.3 million workers exposed).
- OSHA — Final rule: Occupational Exposure to Respirable Crystalline Silica, 29 CFR 1910.1053 (PEL 50 µg/m³, action level 25 µg/m³).
- IARC Monographs Vol. 68 — Silica: crystalline silica inhaled as quartz or cristobalite is carcinogenic to humans (Group 1) (via ILO).
- CDC MMWR — Silicosis Among Pottery Workers — New Jersey (NIOSH/NJSDH joint study; note: OSHA's limit at the time was 100 µg/m³, today's is 50).
- NIOSH — Health Hazard Evaluation Report 2007-0127-3068: Evaluation of Exposures at a Pottery Shop, Cincinnati, OH, August 2008.
- CDC MMWR — Lead Poisoning in a Family of Five from Traditional Glazed Ceramic Ware — NYC, 2017–2022.
- CDC MMWR — Lead Poisoning Following Ingestion of Homemade Beverage Stored in a Ceramic Jug.
- JEMS — 30 Students Affected by Kiln Fumes in Chicago School.
- Ceramic Arts Network — Kiln Venting (kiln fume hazards).
- NY Post (Oct 6, 2026) — California moves to ban engineered stone (31 → 631 silicosis cases; Cal/OSHA Standards Board emergency-rule vote) and IQAir — California aims to ban artificial stone countertops (35 deaths, 58 lung transplants since 2022; Sept 16, 2026 draft emergency rule; >1% crystalline silica threshold).
Statistics are presented as reported by the cited sources. Workplace studies describe the facilities studied; individual studios vary.