OSHA Provides Update on Silica Enforcement Initiative Targeting Engineered Stone
By Abby Roberts
In an educational session delivered on May 21 at AIHA Connect 2025, Jennifer Kim, CIH, MPH, the director of the Office of Health Enforcement at OSHA, updated attendees on the agency’s focused inspection initiative addressing respirable crystalline silica hazards in the engineered stone fabrication and installation industries. According to Kim, the initiative has so far been successful, with OSHA compliance safety and health officers (CSHOs) identifying 59 establishments where workers were exposed to silica concentrations greater than the permissible exposure limit for the substance. However, follow-up will be necessary to determine if establishments adopt measures to reduce exposures and if these measures are effective.
Kim explained that engineered stone is an artificial composite made from silica mixed with resins, pigments, and sometimes metals. Whereas natural granite is between 10 and 45 percent silica, engineered stone is at least 93 percent silica. Cutting or grinding silica may generate respirable silica particles that can settle in the lungs and cause silicosis, an irreversible, sometimes fatal disease. People working with engineered stone may develop acute silicosis within weeks to years, rather than five to 10 years or 15 to 20 years as with more common accelerated or chronic silicosis cases. Furthermore, the additives that make engineered stone more durable and heat resistant than natural stone also make it more toxic.
“In 2015, we realized this exposure to silica in engineered stone workers was really becoming an issue,” Kim said. This led to CDC and OSHA publishing a hazard alert for silica exposures during engineered stone countertop manufacturing, finishing, and installation, which was updated in 2023 to include the revised silica PEL and is in the process of being updated again. OSHA began to review epidemiological studies conducted outside the United States; Kim highlighted three of these studies in her presentation. In 2019, CDC identified 18 fabricated stone workers in four states with silicosis, including two who had died from the disease. And in 2023, the University of California San Francisco in partnership with the University of California Los Angeles found 52 cases of silicosis, the largest cluster identified in U.S. engineered stone workers to date.
“All these studies and all this information brought us to say, “OK, OSHA, what are you going to do about this hazard?’” Kim said.
OSHA already had a national emphasis program dedicated to respirable crystalline silica. The NEP covered workers engaged in manufacturing or finishing engineered stone facilities, as well as those finishing or installing engineered stone offsite, but did not list these processes as high priority, so establishments that employed engineered stone workers were rarely inspected. The focused inspection initiative for engineered stone addresses this need by specifically targeting establishments that employ workers who manufacture, finish, or install engineered stone. The agency especially directs CSHOs inspecting establishments under this initiative to verify that employers are using silica dust controls and safer work methods, such as water spraying systems, wet sweeping, local exhaust ventilation, and thorough housekeeping, to protect workers.
OSHA evaluated the program after 10 months and summarized the findings in a hazard alert document (PDF). At AIHA Connect, Kim summarized the most up-to-date findings as of May 5, 2025. Under the program, 371 inspections had been conducted and 574 silica samples had been analyzed. Of these samples, 117 exceeded the PEL, including 22 that were at least five times the PEL and six that were at least 10 times the PEL. Kim acknowledged that it could be difficult to determine whether these samples represented exposures related to engineered stone and not other sources of silica. “We make the assumption that [a sample] is engineered stone based on the NAICS codes,” she said. As of May 5, 2025, inspections of 59 establishments had been finalized.
Kim also pointed out that CSHOs identified some of the highest silica concentrations in program planned inspections—inspections of establishments selected by the enforcement initiative, rather than due to complains, referrals, or follow-ups. “Without this initiative, it is unlikely that we would have gone into these facilities,” she said.
The most common silica-related violations cited by CSHOs were related to lack of exposure control plans, lack of exposure assessment, neglect of communicating information about silica hazards to employees, and lack of medical surveillance. Common violations not directly related to silica exposures included lack of hazard communication programs, failure to provide medical evaluations, and lack of respiratory protection programs.
In a Q&A session following her presentation, Kim explained that a future step for the enforcement initiative will be to ensure that establishments implement abatement measures for respirable crystalline silica hazards and that these measures are effective. The enforcement initiative addressing silica hazards among engineered stone workers is planned to continue with no set end date.
Abby Roberts is an assistant editor for The Synergist.
Read more coverage of AIHA Connect 2025.
