Image Credit: Getty Images / RYosha

The opinions, claims, conclusions, and positions expressed in this post are those of the author or person quoted and do not necessarily reflect the opinions of the editors, AIHA, The Synergist, or SynergistNOW.

Silica has long been on the radar of occupational and environmental health and safety professionals, but its prominence has increased in the last decade. In part, this is due to the promulgation of OSHA’s final rule on silica in 2016. It also relates to the rising popularity of engineered or artificial stone products, which contain up to 90 percent silica, and the rise of silicosis cases among countertop workers. In November 2025, for example, the California Department of Public Health issued a health advisory for silicosis in workers involved with cutting, grinding, polishing, and cleaning up artificial stone countertops and other products. Surveillance data collected by CDPH show that 447 Californian countertop workers have been confirmed with silicosis since 2019.

Massachusetts also issued a health alert in December 2025, following the confirmation of the state’s first known case of silicosis in an artificial stone worker. Due to the long latency period of silicosis and the high demand for engineered stone products, “additional cases of engineered stone-associated silicosis are, unfortunately, expected to emerge in the future,” Massachusetts public health officials warned in a press release accompanying the alert.

According to Martin Harper, PhD, CIH, FAIHA, silica research has also boomed in recent years. Since 2004, he has organized the Respirable Crystalline Silica and Other Minerals and Metals Symposium, an event for sharing and discussing silica research. Whereas the 2004 and 2012 symposia fit into one- and two-day events, respectively, Harper was taken aback by the volume of submissions he received for the 2026 symposium—enough that he could have hosted four days of content, had it been feasible. “So that's an indication of the growing importance of this subject,” he told SynergistNOW staff.

Developing the Symposium

Harper is well-qualified to gauge the increasing significance of silica. As a former chief of NIOSH’s Exposure Assessment Branch, he was part of a team that advised OSHA on its silica regulations and the administrative hearings held after the regulations were published. He also used to convene the International Organization for Standardization (ISO) committee on workplace atmospheres, as well as its working group on silica.

In past decades, Harper explained, silicosis occurred in “fairly niche” industries, such as coal mining, sandblasting, brick and concrete cutting, and porcelain manufacturing. Silicosis is a lung disease caused by inhaling silica. Although it can be serious and even fatal, it affected relatively few workers, mostly in the construction industries.

In this environment, he organized the first in a series of symposia to report and share new research on silica, which was hosted by ASTM in 2004. Harper hoped the symposium format would generate more discussion between presenters and attendees than at a traditional conference. “With a symposium, we're supposed to have a little bit more dialogue,” he explained. “We're supposed to share and discuss and advise and provide opinions.”

In recent years, however, the rise of artificial stone has resulted in a new worker population becoming at risk for developing silicosis. Many small businesses involved in countertop production must navigate this unfamiliar risk. “These people have little idea about industrial hygiene,” Harper said. “They don't understand that there's a hazard. They don't understand the severity of the hazard. They don't understand how to implement controls or protect the workers. The workers themselves don't realize that there's a problem.” All these factors contribute to new challenges for OEHS professionals working to control silica hazards.

Furthermore, the passage of OSHA’s silica regulations put employers at heightened risk of litigation. The lawyers who take silicosis tort cases are often very energetic. “I have heard they have even sued the companies that make the earth moving machines that were being used on a construction site,” Harper said. “This is actually part of the risk management situation—that not only is there a risk to the worker, there is a risk to the employer too.”

The result has been not only an explosion of silica-related lawsuits, but a flood of new research as well. When Harper first organized the third symposium in 2024, he received enough abstracts to fill the planned two-day event before it was cancelled due to Hurricane Milton. After AIHA agreed to host the symposium in connection with AIHA Connect 2026, Harper received double the submissions, resulting in some presentations being converted to posters to make room for the additional content.

“I didn't realize it was going to be that popular,” Harper said. “Given the number of people who want to present, you have to assume that there's an equal or greater number of people who want to listen.”

What to Expect

According to Harper, the presenters selected for the symposium will represent academic, corporate, consulting, and governmental organizations from eight countries. Because of this diversity, presentations will encapsulate a range of knowledge and experience relating to silica protections. For example, some of the consultants will report on their approaches to communicating and managing silica risks to small businesses that fabricate engineered stone.

Each presenter will receive 15 minutes to speak, followed by five minutes for questions. In a discussion period at the end of the symposium, Harper will pose important questions to participants about the future of silica regulations, such as whether engineered stone should be banned in the United States, as the material has already been banned in Australia. “That's the question of the moment,” Harper said. “Is this the new asbestos?”

Other presentations will address accurately measuring silica hazards, which Harper stressed is essential for regulatory compliance. “You don't know that somebody is exposed above a limit value unless you take a measurement, and that the measurement result is valid,” he explained. Furthermore, taking measurements often requires the employer or OEHS professional to take action. Even if silica levels fall below OSHA’s permissible exposure limit, they may still surpass the action level, compelling an employer to take actions ranging from putting up signs to giving workers respiratory protection and enrolling them in medical monitoring. Respirators are costly, and so is hiring an outside trainer to educate workers. Monitoring workers for silicosis symptoms may change the employer’s health insurance premiums. “Even if your workers don't actually get sick, there's still a fundamental impact,” Harper said.

Lowering the exposure limit for silica may put it below the range of concentrations for which the relevant analytical method has been validated. One presentation will examine the use of devices that collect more sample as a potential solution to this challenge. However, this equipment is often heavy, and workers may not want to wear it. Additional presentations will compare the two main methods used to analyze silica—infrared and X-ray diffraction—and discuss how to improve them.

Further presentations will discuss unusual environments where silica may be found, such as in facilities where aggregate screening, biogas production, use of copper slag, and even horse training occurs. “The soils that they use, that the horses run on, may contain silica,” Harper explained. “And with a lot of horses pawing around on the ground, there's going to be a lot of dust up in the air.”

Major Takeaways

According to Harper, not only will attendees leave the symposium knowing the basic health issues associated with silica exposure, but they will also know where they might encounter silica, what sampling and analytical methods to choose, and how to determine if their lab can analyze silica effectively. They will know what attempts have been made to prevent silica exposures in various situations and whether they were successful. “So your average hygienist will get benefit from all parts of this meeting because they'll hear the latest research, the latest ideas,” Harper said.

Above all, Harper hopes silica symposium attendees will appreciate MSHA’s slogan for a past silicosis prevention campaign: “If it’s silica, it’s not just dust.” If OEHS professionals remember that, he explained, they will better understand what steps they must take to reduce risks from silica. “You can't just treat it as a nuisance,” Harper said.

The 2026 Respirable Crystalline Silica and Other Minerals and Metals Symposium will be held on Saturday, May 30, and Sunday, May 31, as a professional development course in New Orleans. It will be one of the events associated with AIHA Connect 2026, occurring June 1st through 3rd at the Ernest N. Morial Convention Center. To learn more about the Silica Symposium, view the PDC agenda. Register for AIHA Connect 2026 via the conference’s website.

Further Reading

The Synergist: "Protecting Stone Workers: Reducing Exposure to Respirable Crystalline Silica during Stone Countertop Fabrication" (October 2024).