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Introduction	Potential Health Effects
Where can Silica Exposure Occur?	What is a Silica Control Program?
Preparing & Implementing a Silica Control Program	Appendix A: Background Information on Silica

Introduction

Silica refers specifically to silicon dioxide (SiO₂), and is a major component of sand, rock, and mineral ores. Exposure to fine (respirable size) particles of crystalline forms of silica is associated with adverse health effects such as silicosis, lung cancer, chronic obstructive pulmonary disease (COPD), and activation of latent Tuberculosis (TB) infections.

OSHA (Occupational Safety and Health Administration) estimates that more than 2.3 million workers are exposed to respirable crystalline silica in their workplace, with nearly 90% of those workers employed in the construction industry. (OSHA – Silica, Crystalline). Occupational exposures occur when workers cut, grind, crush, or drill silica-containing materials such as concrete, masonry, tile, and rock. About 300,000 workers are exposed in general industry and maritime operations such as brick, concrete, and pottery manufacturing, as well as operations using sand products, such as foundry work and hydraulic fracturing (fracking) of oil and gas wells (https://www.osha.gov/silica/).

Based on the widespread occurrence and use of silica, the number of silicosis-related deaths reported in mortality studies and the health effects of overexposure to silica, OSHA implemented (in May of 1996) a nationwide Special Emphasis Program (SEP) to eliminate silicosis in the workplace. In January of 2008, OSHA established a National Emphasis Program (NEP) which expanded and built upon the 1996 SEP. In August of 2013, OSHA announced proposed rules for General Industry, Maritime, and Construction. The final rules were issued on March 24, 2016 and became effective on June 23, 2016.

More information on silica can be found in Appendix A of the OSHA National Emphasis Program - Crystalline Silica.

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Potential Health Effects

Silicosis related mortality has declined in the U.S. From 1968 to 2005, the number of deaths from silicosis declined from 1,065 in 1968 to 165 in 2004. During 2001–2010, a total of 1,437 decedents had silicosis coded as an underlying or contributing cause of death. The annual number of silicosis deaths declined from 164 in 2001 to 101 in 2010 (CDC – Morbidity and Mortality Weekly Report – February 13, 2005). “The Center for Disease Control (CDC) cited two main factors that were likely responsible for the decline since 1968. First, many of the deaths during the early part of the study period were among workers whose main exposure to respirable crystalline silica probably occurred before introduction of national silica standards established by OSHA and MSHA. The establishment of Permissible Exposure Limits (PELs) likely led to reduced silica dust exposure beginning in the 1970's. Second, employment has declined in heavy industries (e.g., foundries) where silica exposure was prevalent”. (Occupational Exposure to Respirable Crystalline Silica - Federal Register / Vol. 81, No. 58 / Friday, March 25, 2016 / Rules and Regulations)

“Despite this decline, silicosis deaths among workers of all ages result in significant premature mortality. Between 1996 and 2005, a total of 1746 deaths resulted in a total of 20,234 years of life lost from life expectancy, with an average of 11.6 years of life lost. For the same period, among 307 decedents who died before age 65 (the end of a working life), there were 3,045 years of life lost up to age 65, with an average of 9.9 years of life lost from a working life “.(Occupational Exposure to Respirable Crystalline Silica - Federal Register / Vol. 81, No. 58 / Friday, March 25, 2016 / Rules and Regulations).

Workers may develop any of these three types of silicosis, depending on the concentration of airborne silica and duration of exposure.

Chronic Silicosis, the most common form of silicosis, occurs after 15–20 years of moderate to low exposures to respirable crystalline silica. Symptoms associated with chronic silicosis may or may not be obvious; therefore, workers need to have a chest x-ray to determine if there is lung damage. As the disease progresses, the worker may experience shortness of breath upon exercising and have clinical signs of poor oxygen/carbon dioxide exchange. In the later stages, the worker may experience fatigue, extreme shortness of breath, chest pain, or respiratory failure. (OSHA Crystalline Silica Exposure)

Accelerated Silicosis. Accelerated silicosis can occur after 5-10 years of high exposures to respirable crystalline silica. Symptoms include severe shortness of breath, weakness, and weight loss. The onset of symptoms takes longer than in acute silicosis. (OSHA Crystalline Silica Exposure)

Acute silicosis occurs after a few months or as long as 2 years following exposures to extremely high concentrations of respirable crystalline silica. Symptoms of acute silicosis include severe disabling shortness of breath, weakness, and weight loss, which often leads to death. (OSHA Crystalline Silica Exposure)

Since 1968, NIOSH has obtained mortality data from the National Center for Health Statistics (NCHS) for various respiratory conditions, including silicosis. During 2001–2010, 1,437 decedents had silicosis coded as the underlying or contributing cause of death. Of these, 28 (1.9%) were aged 15–44 years, 1,370 (95.3%) were males. The annual number of silicosis deaths declined from 164 (0.74 per 1 million) in 2001 to 101 (0.39) in 2010. A statistically significant decline in silicosis death rates was observed during 2001–2010. However, silicosis deaths still occurred among persons aged 15–44 years. Of 28 decedents aged 15–44 years, the youngest was aged 19 years (Silicosis Mortality Trends and New Exposures to Respirable Crystalline Silica — United States, 2001–2010 - Centers for Disease Control and Prevention - February 13, 2015).

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Where Can Silica Exposure Occur?

Silica is a general term for the compound silicon dioxide (SiO₂). Silica can be crystalline or amorphous. Different crystalline silica forms exist and include quartz and less common forms such as cristobalite and tridymite. In the literature, crystalline silica is commonly referred to as silica sand, free silica, quartz, cristobalite and tridymite.

Crystalline silica is the basic component of sand, quartz, and granite rock. Activities such as sandblasting, rock drilling, roof bolting, foundry work, stone cutting, drilling, quarrying, brick/block/concrete cutting, gunite operations, drywall finishing, lead-based paint encapsulation, and tunneling through the earth's crust can create an airborne silica exposure hazard. In addition, some recently noted exposures to silica include the following.

Calcined diatomaceous earth contains appreciable amounts of cristobalite. Calcination involves the heat treatment of solid material to bring about thermal decomposition. In addition to use as a filtering media, calcined diatomaceous earth is often used in industries such as food and beverage preparation where only food grade products and equipment can come in contact with foods or beverages being made.
Asphalt manufacturing may also be a source of crystalline silica exposure, due to mechanical formation of crystalline silica dust when sand and aggregate passes through rotary dryers. The fine dust can have significant amounts of crystalline silica, depending on the source of the aggregate.
The repair or replacement of linings of rotary kilns found in pulp and paper mills and in other manufacturing locations as well as the linings in cupola furnaces are potential sources of crystalline silica exposure.
In food processing operations where crops such as potatoes and beans are readied for market, silica overexposures have been documented in the sorting, grading, and washing areas.

The OSHA National Emphasis Program - Appendix B contains a listing of industries where overexposure to respirable crystalline silica can occur.

Geologically, quartz is the second most common mineral in the earth's crust, readily found in both sedimentary and igneous rocks. Quartz content can vary greatly among different rock types, for example: granite can contain anywhere from 10 to 40 percent quartz; shales have been found to average approximately 22 percent quartz; and sandstones can average almost 70 percent quartz.

When diatomaceous earth is subject to pressure or is processed (calcined) at temperatures above 1000°C, some of the amorphous silica is converted to crystalline silica in the form of cristobalite. Cristobalite is also created in "after-service" refractive ceramic insulation.

Crystalline silica is commonly found and used in the following industries:
Construction Electronics industry Foundry Industries Agriculture Maritime Mining Industries	Ceramics, clay and pottery, stone and glass industries Railroad industry (setting and laying track) Slate and flit quarrying and flint crushing Manufacture of soaps and detergents Use and manufacture of abrasives

Perhaps the most familiar use of quartz sand is as an abrasive blasting agent used to remove surface coatings prior to repainting or treating. An alert published by NIOSH – Preventing Silicosis and Deaths from Sandblasting (DHHS (NIOSH) Publication Number 92-102) estimates that of the approximately one million American workers at risk of developing silicosis, more than 100,000 are employed as sand blasters.

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What is a Silica Control Program?

To help reduce the likelihood of silica-related disease, an effective Silica Control Program is needed for all employees exposed to respirable silica (quartz, cristobalite and tridymite). One of the potential benefits of a silica control program is reduction of the risk of occupational disease, primarily silicosis. Other potential benefits include improved visibility while working, reduced accident rates, increased work efficiency, and decreased dust levels migrating off-site. Occupational disease arising from exposure to silica reduces quality of life, potentially resulting in early death for the affected individual and increased costs for the employer. A Silica Control Program can benefit both employers and employees.

The basic elements of a Silica Control Program include:

Exposure Monitoring. Exposure to respirable crystalline silica is determined by personal, breathing zone, air sampling. Employee exposures should be controlled below the OSHA Permissible Exposure Limit (PEL) of 50 micrograms per cubic meter of air (µg/m³) for 8-hours, and preferably the OSHA Action Level of 25 µg/m³ for 8-hours, which is the same as the current ACGIH Threshold Limit Value (TLV®) for respirable crystalline quartz and cristobalite. Per the OSHA Silica Standards, the employer must assess the exposure of each employee who is or may be expected to be exposed to respirable crystalline silica at or above the OSHA Action level. The Construction Standard, however, identifies specific engineering and work practice control methods and respiratory protection requirements in Table 1 for 18 specified tasks/equipment.

Stationary Masonry Saws
Handheld power saws
Handheld power saws for cutting fiber-cement board
Walk-behind saws
Drivable Saws
Rig-mounted core saws or drills
Handheld and stand-mounted drills
Dowel drilling rigs for concrete
Vehicle-mounted drilling rigs for rock and concrete

Jackhammers and handheld powered chipping tools
Handheld grinders for mortar removal
Handheld grinders for uses other than mortar removal
Walk-behind milling machines and floor grinders
Small drivable milling machines
Large drivable milling machines
Crushing machines
Heavy equipment and utility vehicles used to abrade or fracture silica-containing materials
Heavy equipment and utility vehicles for tasks such as grading and excavating, but not including demolishing abrading or fracturing silica-containing materials

According to the Construction Standard, initial exposure monitoring would not be required for these tasks when the specified controls and respiratory protection requirements are fully implemented.

Performance Option - Assessing the 8-hour time-weighted average (TWA) exposure for each employee on the basis of any combination of air monitoring or objective data sufficient to accurately characterize employee exposures to respirable silica. Objective data means information, such as air monitoring data from industry-wide surveys or calculations based on the composition of a substance, demonstrating employee exposures to respirable silica associated with a particular product or a specific process, task or activity. The data must reflect workplace conditions closely resembling or with a higher exposure potential than the processes, types of materials, control methods, work practices, and environmental conditions in the current operation.

Scheduled monitoring option - Perform initial monitoring to assess the 8-hour TWA exposure for each employee on the basis of one or more personal breathing zone air samples that reflect the exposures of employees on each shift, for each job classification, in each work area. In representative sampling, sample the employee(s) who are expected to have the highest exposure to respirable crystalline silica.

Periodic Monitoring. If exposure monitoring shows employee exposures are below the OSHA Action Level, additional monitoring (reassessment of exposures) is not required for those employees whose exposure is represented by such monitoring. If the monitoring results are above the Action Level, but below the PEL, monitoring is to be repeated within six months of the most recent monitoring. If the results are above the PEL, monitoring is to be repeated within three months of the most recent monitoring. Employee exposures are to be reassessed, however, whenever a change in the production, process, control equipment, personnel, or work practices may reasonably be expected to result in new or additional exposures at or above the Action Level, or the employer has any reason to believe that new or additional exposures at or above the action level have occurred.
Employee Notification of Results. Employees are to be notified of air sampling results within 15 working days after completion of an exposure assessment (five working days for Construction). Employees are to be notified either individually in writing or by posting the results in an accessible location. Whenever the exposure results are above the PEL, the written notification must describe the corrective actions being taken to reduce employee exposures to or below the PEL.
Regulated Areas. Establish regulated areas wherever an employee's exposure to airborne concentrations of respirable crystalline silica can reasonably be expected to be in excess of the OSHA PEL. The area(s) is to be demarcated in any manner that adequately establishes and alerts employees to the boundaries of the area and minimizes the number of employees exposed to respirable crystalline silica within the regulated area. Warning signs are to be posted at all entrances to regulated areas. REGULATED AREAS ARE NOT REQUIRED BY OSHA FOR CONSTRUCTION.
Written exposure control plan. Establish and implement a written exposure control plan that identifies the tasks in the workplace that involve exposure to respirable silica; a description of engineering controls, work practices and respiratory protection used to limit exposure to respirable silica; and a description of housekeeping measures used to limit exposure to respirable silica. For Construction, the exposure control plan should also include a description of the procedures to restrict access to work areas, when necessary, to minimize the number of employees exposed to respirable silica and their level of exposure, including exposures generated by other employers or sole proprietors. The effectiveness of the exposure control plan is to be reviewed at least annually, and updated as necessary.
Respiratory Protection. Respiratory protection is required (1) where exposures exceed the PEL during periods necessary to install or implement feasible engineering and work practice controls; (2) where exposures exceed the PEL during tasks, such as certain maintenance and repair tasks for which engineering and work practice controls are not feasible; (3) during tasks where implemented engineering and work practice controls are not sufficient to reduce employee exposures below the PEL, and (4) during periods when the employee is in a regulated area (general industry and maritime). Respirator use is to be governed by a Respiratory Protection Program meeting the requirements of OSHA standard 29 CFR 1910.134 - Respiratory Protection.
Engineering and Work Practice Controls. Implement feasible engineering and work practice controls to reduce employee exposures to respirable silica below the PEL, and preferably the Action Level. Engineering controls are the preferred method to reduce airborne crystalline silica exposures. Engineering controls include substitution with less toxic materials, dust suppression methods, and ventilation control measures. Work practice controls systematically modify how employees perform an operation, and often involve employees' use of engineering controls (e.g., proper use of local exhaust ventilation, using wet methods or HEPA vacuuming for cleaning, etc.).
Housekeeping. Prohibit dry sweeping or dry brushing, unless wet sweeping, HEPA filtered vacuuming, or other methods that minimize dust exposure are not feasible. Prohibit the use of compressed air to clean clothing or surfaces, unless used in conjunction with a ventilation system that effectively captures the dust cloud created, or no alternative method is feasible.
Medical Surveillance. Specific medical examinations are to be made available to all workers who will be occupationally exposed to respirable crystalline silica above the OSHA Action Level for 30 or more days per year. For construction, medical surveillance is required for each employee who is required by the Silica Standard to use a respirator for 30 or more days per year.
Informing Employees of Hazards from Crystalline Silica. A training program and Safety Data Sheets (SDSs) are required to inform exposed employees about the hazards of crystalline silica, the specific tasks in the workplace that could result in exposure to respirable silica, and the specific measures implemented to prevent overexposure.
Monitoring and Record keeping Requirements. Specific requirements exist for personal, breathing zone, exposure monitoring, monitoring frequency, method of sample analysis, and maintenance of air monitoring and medical records.

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Preparing and Implementing a Silica Control Program

Identifying Responsible Staff

A Silica Control Program should be a continuing program in your facility. In order to have an ongoing, successful program, responsibility should be assigned for both the initial and ongoing activities. In some cases, these activities already may be part of current job assignments. For example, site supervisors frequently are responsible for on-the-job training sessions. Early identification of the responsible employees, and involvement of them in developing your plan of action, can help result in a more effective program design. Evaluating the effectiveness of your program can also be enhanced by involvement of affected employees.

For any safety and health program, success can depend on commitment at every level of the organization. This is particularly true for silica exposure prevention, where success may require a change in behavior. This may only occur if employers understand the program, are committed to its success, and if employees are motivated by the people presenting the information to them.

The Construction Standard requires that the employer designate a competent person to make frequent and regular inspections of job sites, materials, and equipment to implement the written exposure control plan.

Identifying Employees to be included in a Silica Control Program

With the exception of specific tasks covered in the Construction Standard (Table 1), initial air monitoring is necessary to identify those employees exposed to crystalline silica. Exposure to crystalline silica is determined by personal, breathing zone, air sampling. Employee exposures to respirable silica should be controlled below the OSHA PEL, and preferably the Action Level. All air samples taken to satisfy the monitoring requirements of the OSHA Silica Standards are to be evaluated by a laboratory that analyzes air samples for respirable crystalline silica in accordance with the procedures in Appendix A of the Silica Standards.

The OSHA (ID-142) and NIOSH (7500) Sampling Methods include specific procedures for sampling, calibration of equipment, and analysis of respirable dust samples. Generally, a "high flow" personal sampling pump is used to draw air through a cyclone preselector, or similar particle size selection device, and a preweighed 5 micron (µ) PVC filter. Lab analysis consists of weighing for respirable particulate and X-ray diffraction to determine the percentage of silica in the sample. The respirable dust result can be compared to the OSHA PEL for respirable particulates-Not Otherwise Regulated (PNOR) which is an 8-hour standard of 5 milligrams per cubic meter of air (mg/m³). The silica results are compared to the OSHA PEL and Action Level.

In addition to initial monitoring, the Silica Standards require periodic exposure assessments. The monitoring frequency is based on whether initial monitoring results are above the OSHA PEL and/or Action Level. The Silica Standards also require that additional air monitoring be repeated when changes in production, processes or controls have the potential to increase respirable silica dust exposures. Such changes may mean that additional employees need to be included in the program. You may also want to monitor after implementing changes designed to reduce respirable silica exposures, (e.g., after enclosing a particular machine or area to reduce the number of employees exposed). The monitoring may show that some employees no longer need to be included in all aspects of a Silica Control Program.

Written Silica Control Program

All workplaces where employees are exposed to respirable silica above the PEL should have a written Silica Control Program which describes how the program will be implemented in that facility. Preparation of a plan should not just be a paper exercise—all of the elements should be implemented in the workplace.

The plan does not have to be lengthy or complicated. It can act as a blueprint for implementation of the program—with the goal of ensuring that all aspects of the Silica Standards have been addressed.

The Sample Silica Control Program included in this kit is a generic, hypothetical, example of a written program. Although such general guidance may be helpful, an actual written program should reflect and be specific to the applicable workplace. Therefore, the Sample Program should only be used as a resource, as it must be adapted to address the specific facility it covers. For example, the written plan should list the affected employees or areas at your site, indicate who is to be responsible for the various aspects of the program in your facility, and indicate how any written materials or exposure records will be made available to employees.

A written Silica Control Program should describe the engineering and administrative controls used at your facility or job site, medical management program in place to monitor employee health; respiratory protection provided to the employees and the method of selection; training procedures; and record keeping practices. The following discussion provides descriptions of the program elements based on the Silica Standards that can be used as a reference when developing a Silica Control Program.

Medical

Specific medical examinations are required and made available to all workers exposed to crystalline silica above the OSHA Action Level for 30 or more days per year (General Industry Standard), or are required to use respiratory protection to comply with the Silica Standard for 30 or more days per year (Construction Standard).

Medical Examinations

The Silica Standards require employers provide medical surveillance at no cost to the employee. A baseline examination is to be made available within 30 days after initial assignment, unless the employee has received a medical examination that meets the requirements within the past three years. The examination shall consist of:

A medical and work history with emphasis on: past, present, and anticipated exposure to respirable crystalline silica, dust, and other agents affecting the respiratory system; any history of respiratory system dysfunction, including signs and symptoms of respiratory disease (e.g., shortness of breath, cough, wheezing); history of tuberculosis; and smoking status and history.
A physical examination with special emphasis on the respiratory system.
A chest X-ray
Pulmonary Function Tests (PFT) to include forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) and FEV1/FEC ratio.
Testing for latent tuberculosis; and
Any other tests deemed appropriate by the PLHCP (Physician or other Licensed Health Care Professional).

Medical examinations are to be repeated at least every three years, or more frequently if recommended by the Health Care Professional.

Regulated Areas and Access Control

Whenever an employee's exposure to airborne concentrations of respirable crystalline silica is, or can reasonably be expected to be, in excess of the OSHA PEL, the employer (general industry and maritime) must establish regulated areas and have a written exposure control plan. There are no requirements for Regulated Areas in the Construction Standard.

Regulated Area (General Industry and Maritime)

Per the General Industry Standard, regulated area refers to an area, demarcated by the employer, where an employee's exposure to airborne concentrations of respirable crystalline silica exceeds, or can be reasonably expected to exceed, the PEL. The regulated area(s) is to be demarcated in a manner that minimizes the number of employees exposed to respirable crystalline silica within the regulated area. Access is to be restricted to authorized employees required by work duties to be in the regulated area, designated representatives of the employees for the purpose of observing monitoring procedures, and any person authorized by the OSHA act or regulations issued under it to be in the regulated area. Appropriate respirators are to be provided for those entering the regulated area.

Written Exposure Control Plan (General Industry and Construction)

Per the Silica Standards, the written Access Control Program must contain the following elements:

A description of the tasks in the workplace that involve exposure to respirable crystalline silica;
A description of the engineering controls, work practices, and respiratory protection used to limit employee exposure to respirable crystalline silica for each task; and
A description of the housekeeping measures used to limit employee exposure to respirable crystalline silica.

The Construction Standard requires that the Exposure Control Plan also include:

A description of the procedures used to restrict access to work areas, where necessary, to minimize the number of employees exposed to respirable crystalline silica and their level of exposure, including exposures generated by other employers or sole proprietors.

Respiratory Protection

Per the Silica Standards, respiratory protection is required:

Where specified in Table 1 of the Construction Standard for Respirable Crystalline Silica.
For tasks not listed in Table 1 of the Construction Standard, or where the employer does not fully and properly implement the engineering controls, work practices, and respiratory protection described in Table 1.
Where exposures exceed the PEL during periods necessary to install or implement feasible engineering and work practice controls;
Where exposures exceed the PEL during tasks, such as certain maintenance and repair tasks, for which engineering and work practice controls are not feasible;
During tasks for which an employer has implemented all feasible engineering and work practice controls and such controls are not sufficient to reduce exposures to or below the PEL;
During periods when the employee is in a regulated area (General Industry and Maritime).
During abrasive blasting operations, abrasive blasting respirators (continuous flow air-line respirators - Type CE) are required where abrasive blasting is conducted using crystalline silica-containing blasting agents, or where abrasive blasting is conducted on substrates that contain crystalline silica.

Air sampling results are used to select a respirator with the appropriate protection factor.

Air sampling must be conducted whenever process, work site, climate or control changes occur which are likely to affect the respirable silica concentration, and therefore, respirator selection.
The use of respiratory protection is governed by a respiratory protection program, which meets the requirements of 29 CFR 1910.134/1926.134, Respiratory Protection. The respiratory protection program must include appropriate respirator selection, medical considerations, and training in proper fit testing, use, cleaning and storage.

Informing Employees of Hazards from Crystalline Silica

Training is an integral element of an overall Silica Control Program. When workers understand the reasons for the Silica Control Program's requirements and the need to protect their lungs, they should be better motivated to actively participate in the program and to cooperate by wearing their respirators and participating in the medical management program.

Respirable crystalline silica is to be included in the Hazard Communication Program established to comply with OSHA standard 29 CFR 1910.1200 - Hazard Communication. Ensure that each employee has access to labels on containers of crystalline silica and safety data sheets, and is trained in accordance with the requirements of the Hazard Communication Standard. Per the Silica Standards, the training program should include at least the following information:

The health hazards associated with exposure to respirable crystalline silica. Training should ensure that at least the following hazards are addressed: Cancer, lung effects, immune system effects and kidney effects.
Specific tasks in the workplace that could result in exposure to respirable crystalline silica, especially operations where exposures may exceed the PEL.
Specific measured implemented to protect workers from exposure to respirable crystalline silica including engineering controls, work practices, and respirators to be used.
Content of the Silica Standards.
The purpose and a description of the medical surveillance program.

A training program may be structured in a variety of formats, with different portions conducted by different individuals at different times, as long as the OSHA minimum required topics are covered. All of these topics are included in various audiovisual media available commercially or through safety libraries.

Maintaining records of employee training can help ensure that all employees are appropriately trained. If a training program is already in place, an employer may only need to supplement it with information about the company's Silica Control Program. For example, employers that already are in compliance with OSHA's Hazard Communication Standard may have little extra training to do.

Signs

The General Industry Standard requires warning signs be posted at all entrances to regulated areas that bear the following legend:

Engineering and Work Practice Controls

It is generally accepted that engineering controls are the preferred method to reduce airborne crystalline silica levels. Engineering controls can include substitution with less toxic materials, dust suppression methods and ventilation control measures. Work Practice Controls can include appropriate housekeeping, maintenance and repair operations, hygiene procedures, and establishing prohibited practices.

Engineering Controls

Engineering controls should be used to lower the silica exposure of workers wherever it is economically and technically feasible. Such controls can include, but may not be limited to:

Substitution - eliminating the silicosis hazard by substituting silica with less toxic materials.
Dust Suppression - adding moisture (usually water) to reduce the exposure to airborne respirable silica.
Ventilation - providing local exhaust ventilation and dust collection to capture and remove airborne silica from the breathing zone of employees.
Isolation - full or partial enclosure of machines and processes to reduce and/or eliminate respirable silica exposures. An alternative is to place a barrier between the employee and the exposure source, or isolate the employee from the exposure.

Table 1 in the Construction Standard includes Specified Exposure Control Methods for specific operations.

Inspection and maintenance of engineering controls must be scheduled regularly to ensure their continued effectiveness.

Work Practice Controls

Work Practice Controls include specific work practices (and prohibited practices) concerning housekeeping, maintenance, and repair operations, and hygiene procedures. The following are some examples of work practice controls to consider including in a Silica Control Program:

Housekeeping

Emphasis should be placed on maintaining surfaces free of accumulation of silica dust and on prompt cleanup of spills to help reduce the potential for material to become airborne.
The Silica Standards prohibit the use of compressed air to clean clothing or surfaces unless it is used in conjunction with a ventilation system that captures the dust cloud created by the compressed air, or no alternative method is feasible.
Use of a HEPA-filtered vacuum, or washing down with water, are possible alternatives to using compressed air.

Maintenance and repair operations

Preventive maintenance and prompt repair of equipment should be implemented to help reduce the potential for leakage and collection of dusts containing silica.

Hygiene procedures

Smoking, eating and drinking should be prohibited in areas with potential silica exposure.
Employees' work clothing should be vacuumed before entering the lunch and break area and before removal at the end of the shift.
Cleaning work clothing by shaking or blowing with compressed air should be prohibited.

Recordkeeping

Air sampling information and results, respiratory protection and training, and records of employee notifications should all be maintained to properly document the steps taken to protect employees from silica-related occupational disease.

Air Monitoring Data

Make and maintain an accurate record of all exposure measurements taken to assess employee exposure to respirable crystalline silica. Per the Silica Standards, the record must include at least the following information:

Date of measurement for each sample taken
The task monitored
Sampling and analytical method used
Number, duration and results of samples taken
Identity of the laboratory that performed the analysis
The type of personal protective equipment, such as respirators, worn by the employees monitored
Name, social security number, and job classification of all employees represented by the monitoring, indicating which employees were actually monitored.

Objective Data

Make and maintain an accurate record of all objective data relied upon to comply with the Silica Standards. Per the Silica Standards, this record must include at least the following information:

The crystalline silica-containing material in question.
The source of the objective data
The testing protocol and results of testing
A description of the process, task, or activity on which the objective data were based; and,
Other data relevant to the process, task, activity, material, or exposures on which the objective data were based.

Medical Surveillance

Make and maintain an accurate record for each employee covered by medical surveillance. Per the Silica Standards, the record must include the following information about the employee:

Name and social security number
A copy of the PLHCPs' and specialists' written medical opinions; and,
A copy of the information provided to the PLHCPs and specialists.