New Rule Requires Employers To Assess Silica Exposures In Their Workplaces


What is Silica?

Silica (silicon dioxide), with the chemical formula SiO2, is mostly found in nature as quartz. It contributes more than 10% by mass of the earth’s crust and is mostly obtained by mining or purifying quartz. About 95% of silicon dioxide produced is consumed in the construction industry, e.g. for the production of Portland cement. The most severe exposures to crystalline silica are from abrasive blasting, to clean and smooth irregularities from molds, and foundry castings, or remove paint, oils, rust, or dirt form objects that need to be repainted or treated. Other exposures to silica dust occur in cement and brick manufacturing, asphalt pavement manufacturing, china and ceramic manufacturing and the tool and die, steel and foundry industries. Crystalline silica is used in manufacturing adhesives, paints, soaps, and glass. Additionally, crystalline silica exposures occur in the maintenance, repair and replacement of refractory brick furnace linings.

Exposure Assessment

The new OSHA crystalline silica rule states that workers cannot inhale greater than 50 micrograms per cubic meter of air (50(ug/m3). This refers to dust particles that are small enough to be inhaled and accumulate in the respiratory system. Workplaces need to know what their employees’ exposure levels are to understand if they are meeting the new standard. The only way to know is to measure the air while your workers perform the tasks that could generate airborne silica.

How do I measure the air?

A small, battery-operated pump connected to plastic tubing and attached to a pre-weighed PVC filter contained in a plastic cassette and placed in a cyclone. The system is calibrated for air flow rate. The worker wears the sample pump and filter assembly for the work shift. The time sampled should be representative of the tasks performed over an 8 hour work day. Finally, the filter is sent to a qualified laboratory for analysis and results.

Who can help me?

TTL can help you by providing an industrial hygienist who is skilled and experienced to perform the measurements. You will get data that is truly representative of your work place and your workers will know that their potential exposures are being monitored and managed.

Ms. Mlynek brings over 23 years of practical Industrial Hygiene and Safety experience.  Her expertise includes hazard recognition, worker exposure assessments, Industrial Hygiene monitoring plan development and execution, and control implementation for environmental systems.  Throughout her career, she has helped protect the worker from a variety of health and safety hazards.


Please contact Jean Mlynek at or at (419) 214-5010 or Timothy G. Pedro at for more information.