The All-Wet Counterfactual: Isolating Preventable Silica Risk in Countertop Fabrication
By Paul E. Rosenfeld, M.S., Ph.D., Principal Environmental Chemist, RoseyFields LLC, Santa Monica, California
The engineering fix that existed the whole time
Water suppression during stone cutting and grinding dramatically reduces airborne respirable crystalline silica compared to dry-cutting the same material, a fact documented in occupational hygiene literature for decades before the current engineered-stone silicosis litigation wave began. Dr. Paul E. Rosenfeld, M.S., Ph.D. of RoseyFields LLC has applied this principle directly in California silica exposure litigation through an “all-wet counterfactual” exposure reconstruction methodology (Rivas-Williams, 2023).
Building an actual exposure history first
The methodology begins with reconstructing a worker’s actual documented work history, task by task, across a fabrication career: which specific operations, dry-cutting, dry-grinding, or wet methods, were used, for how long, and at what frequency, drawing on deposition testimony, employer records, and industry-standard task-based exposure data where facility-specific monitoring does not exist.
Constructing the counterfactual scenario
The counterfactual scenario then re-calculates the same worker’s cumulative silica dose under an assumption that wet-cutting methods, understood as an available and OSHA-recommended control technology throughout the relevant period, had been consistently used for every task actually performed, holding the work history constant while changing only the exposure-control variable.
Isolating preventable, not just total, exposure
Comparing the actual and counterfactual cumulative dose calculations isolates the specific increment of exposure attributable to a fabrication employer’s failure to implement widely available dust-control practices, a distinction with direct legal significance where liability turns on whether a defendant’s conduct fell below an established standard of care rather than on the mere fact that silica exposure occurred at all.
OSHA’s own guidance as the counterfactual’s foundation
This methodology is not a litigation invention; OSHA’s hazard alert specifically addressing countertop manufacturing identifies wet methods as a primary, readily available control for respirable crystalline silica, meaning the counterfactual scenario represents an industry-recognized best practice rather than a theoretical, unattainable standard (OSHA, Hazard Alert: Worker Exposure to Silica during Countertop Manufacturing).
Quantifying the exposure reduction wet methods actually achieve
Published industrial hygiene surveys of stone fabrication operations have documented substantial reductions in measured respirable crystalline silica concentrations when wet-cutting methods are used compared to dry methods performing comparable tasks, providing the quantitative basis for the counterfactual dose calculation rather than an assumed percentage reduction (Surasi et al., 2022).
Why the timing of exposure-control knowledge matters
Because the counterfactual methodology depends on wet-cutting having been a known, available control during the specific years of a worker’s exposure, establishing the historical timeline of when this control knowledge became industry-standard is itself an important evidentiary component, distinguishing exposure that occurred before feasible controls were recognized from exposure that continued despite known and available alternatives.
Applying the same logic across related silica matters
The same actual-versus-counterfactual dose comparison framework applied in the Rivas-Williams matter extends to other California engineered-stone fabrication litigation involving comparable dry-cutting exposure histories, including matters addressing product identification and multi-employer liability across a worker’s full fabrication career (Martir-Navarro, 2023).
Why this methodology withstands scrutiny better than a bare exposure estimate
Because the all-wet counterfactual approach relies on the worker’s own documented actual task history rather than a generic industry-average exposure assumption, and ties its control-scenario comparison directly to OSHA’s own published guidance, it offers a more defensible foundation against a reliability challenge than an exposure estimate untethered to either the specific plaintiff’s work history or an independently recognized regulatory benchmark.
Why counterfactual dose modeling has broader application beyond silica
The underlying logic, comparing a worker’s actual exposure to a documented, available-control counterfactual, is a transferable methodology applicable wherever a recognized, feasible exposure-control technology existed but was not consistently implemented, extending well beyond stone fabrication to other occupational exposure settings. Readers interested in Dr. Rosenfeld’s silica exposure assessment work can find more detail at RoseyFields.com.
References
1. Rivas-Williams, et al. v [engineered stone fabrication defendants]. Case No. 23STCV08523, Superior Court of California, County of Los Angeles.
2. Martir-Navarro, et al. v [engineered stone fabrication defendants]. Case No. 30-2023-01370092, Superior Court of California, County of Orange.
3. Occupational Safety and Health Administration. Hazard Alert: Worker Exposure to Silica during Countertop Manufacturing, Finishing and Installation. Washington, DC: US Department of Labor.
4. Occupational Safety and Health Administration. Occupational Exposure to Respirable Crystalline Silica. 29 CFR § 1910.1053.
5. Surasi K, Ballen B, Weinberg JL, Materna BL, Harrison R, Cummings KJ, Heinzerling A. Elevated exposures to respirable crystalline silica among engineered stone fabrication workers in California, January 2019-February 2020. Am J Ind Med. 2022;65(9):701-707.
6. Rose C, Heinzerling A, Patel K, Sack C, Wolff J, Zell-Baran L, Weissman D, et al. Severe silicosis in engineered stone fabrication workers — California, Colorado, Texas, and Washington, 2017-2019. MMWR Morb Mortal Wkly Rep. 2019;68(38):813-818.
7. Fazio JC, Gandhi SA, Flattery J, et al. Silicosis among immigrant engineered stone (quartz) countertop fabrication workers in California. JAMA Intern Med. 2023;183(9):991-998.
8. IARC Working Group on the Evaluation of Carcinogenic Risks to Humans. Silica Dust, Crystalline, in the Form of Quartz or Cristobalite. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Vol 100C. Lyon, France: International Agency for Research on Cancer; 2012.
9. National Institute for Occupational Safety and Health. Engineering Controls for Silica in Construction. Cincinnati, OH: CDC.
10. California Division of Occupational Safety and Health (Cal/OSHA). Emergency Regulation on Respirable Crystalline Silica in Engineered Stone Fabrication. Sacramento, CA: Cal/OSHA; 2024.
11. Agency for Toxic Substances and Disease Registry. Toxicological Profile for Silica. Atlanta, GA: US Department of Health and Human Services.
12. Rosenfeld PE. RoseyFields LLC: Silica and Engineered Stone Exposure Assessment. Santa Monica, CA: RoseyFields LLC; 2026.
13. US Environmental Protection Agency. Revisions to the Guideline on Air Quality Models. 40 CFR Part 51, Appendix W. Fed Regist. 2017;82(10):5182-5235.
14. Gonzalez Sanchez, et al. v [engineered stone fabrication defendants]. Case No. 21STCV06984, Superior Court of California, County of Los Angeles.