What is a Safe Level of Silica Exposure in Community/Residential Situations?
Although there is an OSHA Silica Standard, this only applies to workers based on an 8-hour workday.
In non-occupational situations, as in a residential area or community, this obviously is not adequate to protect individuals since the potential exposure can be 24 hours per day, 7 days a week, 365 days a year.
Accepting the fact that silica has been identified as a cancer causing substance, the concern is well justified. There are many residential areas/communities where the potential for exposure to silica is real. Primary examples are rock quarries, road and building construction, sand and gravel operations, concrete mixing facilities and oil/gas fracking since all three use large quantities of sand.
Sand is the basic source of crystalline silica which is the “silica agent” that produces the disease silicosis (a scarring of the lungs) and lung cancer. Crystalline silica is developed when sand is fractured primarily due to friction to create particles of sharp fractured dust. These sharp particles can be small enough to be inhaled into the lungs where these glass-like sharp particles can scar the delicate lung tissue. If the scarring is significant enough, the scarring progressively damages healthy lung tissue with more scarring and can even lead to total deterioration of lung tissues—the disease called silicosis. At the same time, the scarring can result in development of lung cancer.
There is no recommended, safe level of airborne silica outdoors or in any non-occupational setting. Several states have adopted “safe limits” for non-occupational exposure. They include California, New Jersey, Minnesota, Vermont and Texas.
The dilemma found in these states—or anywhere in the Continental U.S. is that the accepted method for sampling and analysis is the OSHA Method (NIOSH 7500) but this is not sensitive enough to reach the state’s limit of 3.0 ug/M3. (The OSHA limit is 50 ug/M3 and the detection limit is 5 ug/M3).
There are other methods for sampling outdoor air such as PM 10 and PM 2.5 but these methods cannot identify the amount of silica in the sample. The OSHA method considers respirable silica, often referred to as PM 4.0, and specifically identifies the amount of silica in the sample.
Now, a new method exists that can achieve the state’s limit of 3.0 ug/M3 of PM 4.0, identifies the silica content, and can reach the analytical sensitivity to achieve the 3.0 ug/M3 level by sampling for 8 hours or longer. The method uses a SKC, Inc. sampling cassette and samples at 8 LPM (liters per minute) and analyzes the sample by the accepted method of NIOSH 7500.
Atlantic Environmental, Inc. has the equipment and knowledge to use this method to sample outdoors or in any building (commercial/residential) to determine if the silica levels are within the recommended level of 3.0 ug/M3.
Contact us at firstname.lastname@example.org or call us at 1-800-344-4414 for more details or a quote.
Environmental Working Group (EWG), “Danger in the Air: Health Concerns for Silica in Outdoor Air,”www.ewg.org/research/sandstorm/health-concerns-silica-outdoor-air
Public Lab, Silica Monitoring, www.public lab.org/wiki/silica-monitoring
Bhagia, J.L., “Non-Occupational Exposure to Silica Dust,” Indian Journal of Occupational and Environmental Medicine, September-December 2012, 16 (3), pages 95-100.
Gehrke, G., “Airborne Silica and Regulations,” Public Lab, publiclab.org/notes/mlamadrid/06-21-2016\airborne-silica-and-regulations
Our primary service areas for silica sampling are: NJ, NY, NYC, PA, CT, DE, (Boston) MA, RI, Wash DC, WI, MD, MI, (Chicago) IL, VA, IN, (Atlanta) GA, AL, NC, SC, TN, (Dallas, Ft. Worth) TX, OK, DC, AR, we can service most other areas of the U.S. but with some added travel charges.