Article by Gregory Havel
In July 2017, the U.S. Occupational Safety and Health Administration (OSHA) began enforcement of new regulations on the exposure of construction and demolition workers to respirable silica dust. These regulations are free downloads from www.osha.gov. On the Web site, look for “Standards and Regulations,” click on “Construction,” and scroll down to 29 CFR 1926.1153.
The silica pages on the OSHA and National Institute for Occupational Safety and Health (NIOSH) Web sites provide this information on silica:
- Silica is a white or clear crystalline substance that appears granular
- Silica is Silicon Dioxide, with the chemical formula SiO2
- Silica is one of the most common compounds found on the earth, and is the compound from which quartz and sand in much of the world are made
Silica can be found almost anywhere on our world, as particles ranging in sizes from large rocks to sand grains to microscopic particles. It is used in construction materials, concrete, Portland cement, electronics, and as an ingredient in some foods and medications.
It is the microscopic particles that are the health concern when inhaled. Respirable crystalline silica particles are less than 1/100 of the size of a grain of beach or playground sand, and are created when silica-containing materials like stone, rock, concrete, brick, block, and mortar are cut, sawed, ground, drilled, and crushed. These respirable particles can easily become and remain airborne, and be inhaled by workers at construction job sites.
Workers who inhale these very small crystalline silica particles are at increased risk of developing serious silica-related diseases, including:
- Silicosis, an incurable lung disease that can lead to disability and death
- Lung cancer
- Chronic obstructive pulmonary disease (COPD)
- Tuberculosis
- Kidney disease
Exposure to respirable crystalline silica is also related to the development of auto-immune disorders like lupus and rheumatoid arthritis, as well as cardiovascular impairment.
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Silicosis usually develops after 15 or more years of occupational exposure to respirable crystalline silica; although it may develop after a comparatively short exposure if the concentration of respirable particles is great enough.
This last point may be an explanation for the large number of emergency responders from the World Trade Center attacks on September 11, 2001 who are ill and dying as the result of their response to the incidents, and as the result of the hours each day for weeks that they contributed to the rescue and recovery activities that followed.
According to the news media at the time, OSHA was working with public health officials and the Fire Department of New York in determining the personal protective equipment and respirators needed by workers at the site.
According to the standards of that time, the permissible exposure limit (PEL) for respirable silica was higher than that for nuisance dust. According to the PEL Table Z-3 in 29 CFR 1910.1000 (2006 edition), the PEL for respirable silica was 10 milligrams per cubic meter of air (mg/m3); and for respirable nuisance dust 5 mg/m3. A disposable dust mask was considered adequate respiratory protection for most of the rescue and recovery workers.
According to today’s standards, stated in 29 CFR 1926.1153, the action level for respirable silica is 25 micrograms per cubic meter (μg/m3), calculated as an eight-hour time weighted average (TWA), while PEL for respirable nuisance dust is still 5 mg/m3
Respirable silica is now recognized as a greater health hazard than it was in 2001. The levels of protection for workers in contaminated areas is greater now than in 2001. Air sampling and testing on construction and demolition job sites has shown that wet cutting and drilling and the use of wet methods during demolition and debris handling suppress dust and reduce the levels of respirable silica dust to nearly zero. OSHA’s silica regulations today will permit the use of disposable dust masks for some kinds of tasks for periods greater than four hours only if the drilling, cutting, or material handling are being done with enough water to suppress visible dust. See Table 1 in OSHA’s 29 CFR 1926.1153 for details on these procedures.
Where will we find silica in buildings and construction materials? Nearly everywhere, including but not limited to: Concrete, concrete masonry units, brick, firebrick, gypsum drywall board and taping compounds, plaster, asphalt paving, Portland cement, mortar, fiber-cement siding, ducts and pipes, ceramic tiles, grout, terrazzo, vinyl composition tiles, some types of insulation, sand, gravel, and roofing materials.
This new silica standard from OSHA, the presence of silica in so many common building materials, and the presence of other hazardous and toxic products (including carbon monoxide, cyanides, asbestos, lead, acids, and other chemicals) in buildings after fires should make use of self-contained breathing apparatus and full firefighter PPE mandatory for work in the fire building until overhaul is complete. Firefighters should also be required to undertake gross decontamination of their PPE at the building exit with a low-pressure water hose before any parts of the PPE are removed.
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Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 35-year veteran of the fire service. He is a Wisconsin-certified fire instructor II, fire officer II, and fire inspector; an adjunct instructor in fire service programs at Gateway Technical College; and safety director for Scherrer Construction Co., Inc. Havel has a bachelor’s degree from St. Norbert College; has more than 35 years of experience in facilities management and building construction; and has presented classes at FDIC.
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