23.2 Identification of Respirable Silica Hazard
23.3 Activities Requiring Control Measures
23.4 General Control Procedures
23.6 Personal Protective Equipment
23.2 Identification of Respirable Silica Hazard #
Project managers and supervisors should identify silica containing materials prior to the beginning of a project or process that may generate airborne respirable particulates. Information provided by manufacturers such as safety data sheets may be used to determine silica content of materials. Materials that commonly contain silica include:
- asphalt
- brick
- cement
- concrete
- concrete block
- drywall
- drywall mud
- fiber cement products
- grout
- gunite/shotcrete
- mortar
- paints with silica aggregate
- plaster
- rock
- roof tile
- sand
- soil
- stone
- stucco
- terrazzo
- tile
EHS should be contacted in order to evaluate work practices that involve materials with unknown silica content.
23.3 Activities Requiring Control Measures #
Specific activities affecting known or assumed silica, that are considered to require exposure and emission control measures include, but are not limited to:
- sanding
- scraping
- cutting
- grinding
- scarifying
- welding
- demolition
- drilling
- sand or abrasive blasting or cleaning
MIOSHA Part 690 Table 1 lists 18 common construction tasks (and the equipment used) that create high levels of silica dust. The table also describes the engineering controls, work practices, and respiratory protection necessary for each task. For each employee engaged in a task identified on Table 1, the employer shall fully and properly implement the requirements specified.
For work tasks not listed in Table 1, or when exposure controls listed are not feasible or create unsafe conditions, all of the following shall be followed:
- All feasible engineering and work practice controls shall be used to reduce employee exposure as low as possible.
- An exposure assessment (EA) shall be performed, which includes air monitoring, to assess employee exposures.
- Personal protective equipment shall be utilized in accordance with this program.
- A HEPA filtered vacuum shall be used to maintain good housekeeping practices.
- Dry sweeping and use of compressed air to clean clothing or surfaces shall be prohibited.
23.4 General Control Procedures #
Prior to disturbance of silica containing materials, employees should successfully complete a Silica Competent Person training, utilize engineering controls, follow specific work practices, and be trained on respiratory protection specified in Table 1.
For each work task that generates airborne silica, a written Exposure Control Plan (ECP) shall be developed and implemented. The ECP shall describe the work task, include a description of the controls used to minimize or prevent exposure and add a description of the housekeeping measures used to limit employee exposure. The ECP shall be reviewed, evaluated, and updated annually by a Qualified Person. EHS should be contacted in order to develop an ECP, if a current plan is not available. An ECP can be developed for silica dust generating tasks using the Interactive Silica Exposure Control Plan form located in the Related documents header above.
For tasks not listed in MIOSHA Table 1, or tasks performed without using controls recommended by MIOSHA, an ECP shall be developed. In addition, an exposure assessment (EA) shall be performed, including representative air sampling in the employee’s personal breathing zone. The exposure assessment shall be specific to each material, process, task, activity, and workplace conditions. The following steps should be performed:
- Implement engineering and work practice controls that minimize employee exposure to respirable silica based upon the ECP. Examples of control measures are as follows:
- Water delivery with continuous stream or spray to surface where dusts are generated;
- Use local exhaust ventilation with HEPA filtration;
- Equip tools with a hood or shroud and dust collection system with HEPA filtration;
- Perform housekeeping practices that minimize generation of dust.
- Periodically evaluate control measures to ensure effectiveness and update the exposure control plan. This should be performed at least annually.
For measures implemented that include an enclosed cab or booth, ensure the cab or booth:
- Is maintained as free as practicable from settled dust.
- Has door seals and closing mechanisms that work properly.
- Has gaskets and seals that are in good condition and working properly.
- Is under positive pressure maintained through continuous delivery of fresh air.
- Has intake air that is filter through a filter that is 95% efficient in the 0.3-10.0 m range (e.g., MERV or better)
- Has heating and cooling capabilities.
23.5 Air Monitoring #
When utilizing engineering controls, work practice and personal protective equipment for work tasks as outlined in MIOSHA Table 1, air monitoring is not required.
When the work task is not identified in MIOSHA Table 1, or when controls are not feasible or create a hazardous condition, EHS should be contacted to perform an exposure assessment (EA) to determine respiratory protection requirements. The EA should represent the exposure of a representative fraction of employees working on the same shift, performing the same task and in the same work environment. The EA shall encompass full-shift or 8-hour TWA air sampling.
At any time worker exposure levels are found to be above the action level (AL), the activity being monitored shall be stopped and be reevaluated for potential problems. A follow up EA should be performed within six (6) months. Following two consecutive EAs, with employee exposures below the AL, air monitoring may be discontinued.
At any time worker exposure levels are found to be above the PEL, the activity being monitored will stop and be reevaluated for methods to reduce exposure levels. A follow up EA shall be performed within three (3) months.
Exposure assessments shall be periodically reassessed whenever a change in 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 when the employer has any reason to believe that new or additional exposures at or above the action level have occurred
Employees shall be notified in writing of the EA results within 5 working days from the end of the assessment. Whenever an EA indicates that employee exposures are above the PEL, a written notification of actions to be taken to reduce exposure to or below the PEL shall be provided to the employee.
23.6 Personal Protective Equipment #
Each employee in the work area shall wear respiratory protection with a minimum assigned protection factor (APF) as identified in MIOSHA Table 1, and when controls in MIOSHA Table 1 are not fully implemented. For Tasks not identified in MIOSHA Table 1, or when controls are not fully implemented, the assigned protection factor of the respirator shall be sufficient in reducing employee exposure below the PEL.
Hand, eye and face protection, and protective coveralls will be used as necessary to protect workers from contamination, irritation or other injuries.
23.7 Housekeeping #
Dry sweeping and/or dry brushing are prohibited where such activity could contribute to employee exposure to silica, unless wet sweeping, HEPA-filtered vacuuming or other methods that minimize the likelihood of exposure are not feasible.
Use of compressed air to clean clothing or surfaces shall be prohibited unless used in conjunction with an effective ventilation system or no alternative is feasible.
23.8 Training #
All employees that may reasonably be expected to have an occupational exposure to respirable crystalline silica shall be provided with Silica Competent Person Training. Training will be provided as necessary thereafter unless there is documented cessation in work activities.
Silica Competent Person training shall include the following:
- An overview of health hazards associated with exposure to crystalline silica.
- Common silica containing materials and job tasks that generate respirable particulates.
- A description of work tasks that could result in exposure to respirable crystalline silica, work restrictions and limitations.
- Routes of exposure and health hazards associated with exposure to respirable crystalline silica.
- Methods for identifying silica containing materials.
- An explanation of occupational exposure levels including MIOSHA PELs.
- A description of work tasks that could result in exposure to respirable crystalline silica.
- Proper selection and limitations of personal protective equipment, including respirators.
- Methods for controlling employee exposure to respirable crystalline silica, including engineering controls, work practices, and respiratory protection.
- An outline of the roles and responsibilities of the Competent Person.
- Requirements of the ECP and methods for evaluating controls outlined in the plan.
- Proper selection of respiratory protection.
- Tool specific training, including operation and maintenance of dust control devices prior to operation of the equipment.
- The contents, purpose and a description of the medical surveillance program.
The employer shall make a copy of any applicable MiOSHA standard(s) readily available without cost to the employee. Silica Competent Person training shall include an assessment to evaluate the employee’s comprehension of the subject matter.
Re-training shall be provided to employees when there is a change in this program, a change in the employee’s job assignment, or when an employee demonstrates a lack of understanding or negligence when working with silica hazards.
23.9 Medical Surveillance #
Workers who are required to wear a respirator for silica exposure for more than 30 days per year shall be included in the Medical Surveillance Program. The program includes a medical and work history questionnaire, an initial examination (within 30 days of assignment), a periodic medical examination (at least every three years), chest x-rays, pulmonary function test and baseline tuberculosis testing. Medical examinations shall be performed by a physician or other licensed health care professional (PLHCP). The PLHCSP may recommend more frequent medical examinations based upon certain risk factors. Additional requirements per the Respiratory Protection Program may be required.
23.10 Recordkeeping #
Written Exposure Control Plan: #
A copy of the Exposure Control Plan (ECP) shall be maintained and kept on file for at least 30 years. The ECP shall include all exposure measurements, description of work tasks; dates; sampling and analytical methods; number, duration and results of sample taken; identity of the laboratory; documentation of PPE used.
The name, employee identification number and job classification of all employees represented by the air monitoring indicating which employees that were actually monitored. Copies of the ECP for each project will be kept at the work site until the project is completed. Once the project is completed, copies of all ECP’s, air monitoring results, waste manifests, and all other relevant documents and information will be consolidated and forwarded to EHS.
Other Records #
All air monitoring results will be compiled and cross indexed by worker name, activity and location. Written copies of representative air monitoring results will be supplied to each worker for each project or site air monitored within 5 days of receipt. All air monitoring reports will have copies stored at EHS.
All essential medical surveillance information will be stored at EHS. Other medical surveillance records will be kept at the medical clinic under control of a physician.
Written opinions of medical surveillance results will be given to individual employees as they are received or within 5 days of receipt.
