Silica Dust Exposure Limits Set by OSHA To Ensure Safety
A new Occupational Safety and Health Administration (OSHA) rule regarding respirable crystalline silica dust exposure in the construction industry requires covered employers to comply with stricter exposure limits and take steps to protect workers. OSHA reduced the exposure for construction activities to 20 percent of the previous permissible limit (from 250 micrograms per cubic meter of air to 50) averaged throughout an eight-hour shift. The previous standard had been in place since 1971. These new regulations for the construction industry went into effect last fall.
Crystalline silica is a common earth mineral that can be found in sand, stone and other materials. Respirable crystalline silica – very small particles, at least 100 times smaller than ordinary sand – is generated when cutting, sawing, grinding, drilling and crushing stone, rock, concrete, brick, block and mortar, among others, as well as in general excavation. The smaller the particles, the deeper they penetrate into the respiratory tract.
Silica Dust Exposure Outcomes
“Silica particles are thrown into the air, and at 10 micrograms they get into your mouth and the top of your throat,” said attorney and author James R. Waite, Esq., who helps companies comply with regulatory standards. “At three to five micrograms, it gets into the chest area and under 2.5, silica dust settles into the lungs and never leaves, which can lead to silicosis and other conditions.”
Silicosis is an incurable lung disease that can result in death or disability. Lung cancer, chronic obstructive pulmonary disease and kidney disease can also result from respirable silica dust exposure. OSHA estimates the updated standard will prevent 600 deaths and more than 900 cases of silicosis annually.
Options and Added Steps With New Exposure Limits
About 2.3 million people in the United States are exposed to silica at work each year. Employers have options to meet the standard, such as using water to keep dust from getting into the air and proper vacuum dust-collection systems that include HEPA filtration. Utilizing approved respirators with an assigned protection factor of at least 10 under certain conditions, such as sawing more than four hours per day outside or anytime inside, is required.
Additional Requirements of the New OSHA Standard Include:
- Assessing employee exposure to silica, if it is at or above an action level of 25 micrograms per cubic meter of air averaged throughout an eight-hour day and limiting access to high-exposure areas.
- Establishing and implementing a written exposure-control plan, which identifies tasks that involve exposure as well as methods used to protect workers, including procedures to restrict access to work areas where high exposures may occur.
- Designating a competent person to implement the written control plan.
- Restricting housekeeping practices that expose workers to silica, such as the use of compressed air without a ventilation system to capture the dust and dry sweeping where effective, safe alternatives are available.
- Offering medical exams – including chest X-rays and lung-function tests – every three years for workers who are required by the standard to wear a respirator for 30 or more days in a given year.
- Training workers on the health effects of silica dust exposure, workplace tasks that can bring them into contact with silica and implementing alternative means of limiting exposure.
- Keeping records of workers’ silica dust exposure and medical exams.