According to OSHA, about 2.3 million people in the U.S. are exposed to silica at work. Exposure to respirable crystalline silica is related to the development of autoimmune disorders and cardiovascular impairment. These occupational diseases are life-altering and debilitating disorders that annually affect thousands of workers across the United States. To protect workers exposed to respirable crystalline silica, OSHA has issued two respirable crystalline silica standards: one for construction and the other for general industry and maritime.
What is Crystalline Silica?
Crystalline silica (silica) is a common mineral found in sand, concrete, stone, and mortar materials. Silica becomes hazardous when reduced to dust and released into the air where it can be inhaled, called respirable silica. This commonly occurs in operations involving cutting, sawing, drilling, and crushing materials that contain silica.
Operations in which sand products are used, such as glass manufacturing, metal casting, and sandblasting, also tend to generate respirable silica
Commonly used construction equipment includes:
- Handheld powered chipping tools
- Vehicle-mounted drilling rigs
- Milling equipment
- Crushing machines
- Heavy demolition equipment
The operations utilizing these types of equipment subject their workers to silica exposure if proper processes are not created, implemented, and monitored
Why is Crystalline Silica so Hazardous?
When silica dust particles are inhaled, they can penetrate deep into the lungs and cause disabling and sometimes fatal diseases, including silicosis, lung cancer, chronic obstructive pulmonary disorder, and kidney disease. Silica looks like dust, but it’s much more harmful to your lungs. It is a human lung carcinogen and breathing it in causes scar tissue formation in the lungs, reducing their ability to take in oxygen.
Without proper protection, exposure poses a serious threat to workers, including silicosis.
As silicosis progresses, you may have shortness of breath when exercising, followed by experiencing fatigue, extreme shortness of breath, chest pain, and respiratory failure.
Acute silicosis occurs only a few months and up to two years following extremely high exposure. Acute silicosis typically leads to death. Accelerated silicosis occurs after 5 to 10 years of increased exposure.
What Does the Standard Require?
The standard requires that employers limit worker exposure to respirable crystalline silica and take other steps to protect workers. OSHA estimates that more than 840,000 of these workers are exposed to silica levels that exceed the new permissible exposure limit (PEL). OSHA first set PELs for respirable silica in 1971, allowing 100 µg/m3 for general industry and 250 µg/m3 for construction and shipyards. Since then, numerous advanced scientific studies have determined that much lower levels of silica exposure can cause serious health effects. 50 µg/m3 PEL is the lowest level that most affected operations can reasonably achieve using:
- Engineering controls
- Work practices.
In its final rule, OSHA issued two different standards for protecting workers from exposure to respirable crystalline silica, one for the construction industry and another for the general and maritime industries. OSHA has not issued regulations for the agriculture sector.
What Are the Exposure Control Requirements?
To comply with exposure control requirements, general industry and maritime employers must measure respirable silica levels in the workplace at any time they may possibly be at or above 25 µg/m3, which is the action level. This is not a lot of exposure and can occur quickly. Employers must limit access to high levels using dust control measures:
- Wetting- is the primary component of minimizing airborne exposure.
Employers must have a written respiratory protection program in place.
What Are the Construction Control Requirements?
Construction employers can either use those same methods or follow specific dust-control methods outlined in Table 1 of OSHA’s final rule.
Employers can either use a control method laid out in Table 1 of the construction standard or measure worker exposure to silica and independently decide which dust controls work best to limit exposures to the PEL in their workplaces.
What is Table 1?
Table 1 provides a list of everyday construction tasks and matches the tasks with dust control methods so employers know exactly what they need to do to limit worker exposure to silica. Employers who correctly follow Table 1 are not required to measure worker exposure to silica and are not subject to the PEL.
Employers who do not use control methods in Table 1 must do the following:
- Measure the amount of silica that workers are exposed to if it may be at or above an action level of 25 micrograms of silica per cubic meter (μg/m3) of air, averaged over an eight-hour day.
- Protect workers from respirable crystalline silica exposures above the PEL of 50 μg/m3, averaged over an eight-hour day.
- Use dust control methods to protect workers from silica exposures above the PEL.
- Provide respirators to workers when dust controls cannot limit exposures to the PEL.
The Silica Written Exposure Control Plan
Construction companies are required to have a written exposure control plan. Minimum requirements include a description of all tasks that workers may have to do that could expose them to respirable silica and a description of the employer’s methods for protecting workers, including procedures used to restrict workers’ access to potential high-exposure areas. Each task that could generate respirable crystalline silica must be identified, and using Table 1, implement control measures to be added to the written plan.
Employers must offer medical exams to workers who may be exposed to respirable silica levels of 25 µg/m3 or more for 30 or more days per year.
The exams must be offered every three years and must include chest X-rays and lung function tests.
OSHA’s Medical Surveillance Guidelines provide the following: Medical screening and surveillance allow for early identification of exposure-related health effects in individual employees and groups of employees so that actions can be taken to both avoid further exposure and prevent or address adverse health outcomes. Silica-related diseases can be fatal, encompass a variety of target organs, and may have public health consequences when considering the increased risk of latent tuberculosis (TB) infection becoming active. Thus, medical surveillance of silica-exposed employees requires that PLHCPs have a thorough knowledge of silica-related health effects.
General Crystalline Silica Safety Precautions
When working with silica, take the following precautions to protect yourself and others.
- Use all available work practices—water sprays, ventilation systems, and blasting cabinets—to control dust exposures.
- If you’re working with new material, check the label for silica. If silica is listed, refer to the product’s Safety Data Sheet (SDS) for more information.
- Every time, be sure to wear proper personal protective equipment. When respiratory protection is required, wear only an N100 NIOSH-certified respirator or a Type CE abrasive-blast supplied-air respirator for abrasive blasting. Make sure you are properly trained and do NOT alter the respirator.
- Always inspect your respirator before use. Alert your supervisor and replace your respirator if you find a crack, puncture, tear, leak, or other unusual condition.
- Be sure to inspect your respirator before use and alert a supervisor if you find a crack, puncture, tear, leak, or any other unusual condition.
- Shave facial hair when you’re working in environments that require a respirator to ensure a good seal between your face and the respirator.
- Wear disposable or washable work clothes and shower if facilities are available
- Don’t eat, drink, smoke, or apply cosmetics in areas where silica dust is present. Wash your hands and face outside of dusty areas before performing these activities.
Understanding OSHA and MSHA requirements
Understanding silica and silica exposure increases awareness of associated health hazards and creates a safe and healthy workplace. Resources are available to help you mitigate exposure to Respirable Crystalline Silica. Working with your management team and staff to create a safety culture and mindset will deliver successful OSHA and MSHA compliance.
Catamount Consulting provides mining, construction, and general industry businesses with specialized safety services, consultation, and compliance strategies. We have the highest regard for quality and employee safety and can facilitate creating a safety culture in your organization. Contact us to learn more about Respirable Crystalline Silica and silica exposure in your workplace.
Click here to view the webinar and learn more about handling an OSHA inspection.
Special thanks to our presenter, Joe Keenan, MBA, CSP from Catamount Consulting.