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    Silica StandardRespirable Crystalline Silica

    Also known as: Respirable crystalline silica standard

    Definition

    Two US OSHA standards for respirable crystalline silica: 29 CFR 1910.1053 for general industry and maritime, and 1926.1153 for construction.

    Editorial definition: The QHSE Standard, updated 3 October 2026 · https://qhsetech.com/glossary/silica-standard

    Scope: General industry and maritime use an 8-hour time-weighted PEL of 50 micrograms per cubic metre; construction has a separate standard.

    Sources checked: . Examples are editorial illustrations.

    What OSHA's two respirable crystalline silica standards say

    OSHA has two standards for respirable crystalline silica. Section 1910.1053 covers general industry and maritime and excludes construction work, agricultural operations and sorptive clay processing, while 1926.1153 covers construction. Each sets a permissible exposure limit of 50 micrograms per cubic metre of air, calculated as an 8-hour time-weighted average, and an action level of 25 micrograms per cubic metre on the same basis. The general industry section says it does not apply where objective data show that exposure will stay below the action level. The construction section has a similar exception for work where exposure stays below that level under foreseeable conditions.

    Both require a written exposure control plan describing the tasks that involve silica, the controls, work practices, respiratory protection and housekeeping, and the construction version adds access restriction procedures, and both require it to be reviewed each year. In general industry the employer assesses exposure either through a performance option, using air monitoring or objective data, or through a scheduled monitoring option with initial, periodic and repeat sampling. Regulated areas are marked where exposure exceeds, or could reasonably exceed, the limit. Construction adds a table of specified exposure control methods for listed tasks such as saws, drills and grinders, with requirements that depend on how long the task lasts in a shift, and a competent person who inspects frequently.

    Medical surveillance has a different trigger in each. In general industry it applies to an employee exposed at or above the action level for 30 or more days a year, with examinations at least every three years or sooner if the health professional recommends it. In construction it applies to an employee required to use a respirator for 30 or more days a year. OSHA's general industry page gives 23 June 2018 for general compliance, 23 June 2020 for medical surveillance of employees at or above the action level and 23 June 2021 for engineering controls in hydraulic fracturing, and the standard says it took effect on 23 June 2016. OSHA's emphasis list also has a silica directive, CPL 03-00-023, dated 4 February 2020. This page is general information, not legal advice.

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    What a silica record set looks like in software

    • A task inventory showing where silica-containing material is cut, ground, drilled, crushed or handled, by site and crew.
    • Exposure results by employee and task, with the sample date, the duration, the method and the result compared with the action level and the limit.
    • The assessment option used for each group, the schedule for repeat sampling and the objective data relied on.
    • The written exposure control plan with its annual review dates, and for construction the table entries used and the competent person named.
    • Records of controls in use, such as water delivery or local exhaust, with inspection results and fixes.
    • Medical surveillance eligibility counted in days a year per employee, with examination dates and referral dates.
    • Regulated area markings, respirator use records and training dates.

    General industry, construction and the limit

    The two standards share a limit and an action level but not every duty, so a record has to say which standard a task falls under. The action level and the limit are different numbers with different consequences, and a result can sit between them. The medical surveillance trigger is counted in days a year, either at or above the action level or in respirator use, so it is not decided by one sample. The word silica alone does not say which compliance date, trigger or table applies to a task.

    A hypothetical example: three results in a stone shop

    This case is invented to illustrate the record and describes no real company. A fabrication shop in general industry samples three workers over a full shift and reports 8-hour time-weighted averages of 18, 31 and 57 micrograms per cubic metre. Against an action level of 25 and a limit of 50, worker A is below the action level, worker B is above it but below the limit, and worker C is 7 above the limit. Two of the three results, 31 and 57, are at or above the action level, and worker B is 6 above the action level and 19 below the limit. The sampling record keeps the duration of each sample and the task being done.

    The shop counts days at or above the action level over the year: 40 for worker B and 45 for worker C, so both reach the 30-day trigger for medical surveillance, and worker A does not. The plan is reviewed, the controls for worker C's cutting station are examined and the sampling schedule is updated, with each step linked to the result that prompted it.

    Common misunderstandings about the silica standard

    • There is not one silica standard. OSHA has separate sections for general industry and maritime and for construction.
    • The action level is not the limit. A result of 31 is above the 25 action level of this example and below the 50 limit.
    • A single sample does not decide medical surveillance. The trigger is days a year at or above the action level, or days of required respirator use in construction.
    • A written plan is not written once. Both standards describe it as reviewed each year.
    • Compliance dates are not all the same. OSHA's page gives different dates for general compliance, medical surveillance and hydraulic fracturing.

    How the silica standard relates to other glossary terms

    Silica records lean on control choices, protective equipment and enforcement terms.

    • Hierarchy of controls: the order in which controls such as water suppression and ventilation come before respirators.
    • PPE: the respirators and other items that the standard treats as part of the controls.
    • OSHA NEP: the emphasis programme list that includes a silica directive.
    • COSHH: the Great Britain framework for substances hazardous to health, a different legal regime.

    Records and evidence that usually exist for the silica standard

    • Exposure monitoring results and the objective data relied on.
    • The written exposure control plan and its annual reviews.
    • Records of controls and their inspection.
    • Medical surveillance and referral records.
    • Training records and respirator programme records.
    • Notes on regulated areas and the signs displayed.
    • Objective data and the conditions under which they apply.

    What a software tool needs to capture for the silica standard

    • Sampling results by worker, task and date with the 8-hour average and the units.
    • Comparison fields for the action level and the limit that show which a result exceeds.
    • A day counter per employee that supports the 30-day surveillance trigger.
    • A plan record with review reminders and linked controls.
    • A task field that separates general industry from construction work.
    • Separate access for health records and exposure data.

    Catalog profiles documenting industrial hygiene and exposure monitoring

    The list comes from the industrial hygiene rule. It does not show that a product holds silica sampling results, applies the OSHA limit or counts surveillance days, which should be tested with a sample data set.

    Same rule for every product: tagged “Industrial Hygiene”, “Occupational Health” or “Chemical Management”, with a sourced industrial hygiene or exposure assessment capability in its record, or one the vendor stated to us, labelled as vendor-stated. Documented and conditional capabilities qualify; check the linked scope before treating a module as included.

    Tekmon pays for a sponsored placement (above); its place in this list follows the same rule as every entry. How lists are ordered

    All 4 matching profiles are shown. Documentation review, not hands-on testing or a claim of compliance.

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    Frequently asked questions

    What are the OSHA limits for respirable crystalline silica?

    Both standards set a permissible exposure limit of 50 micrograms per cubic metre and an action level of 25, each as an 8-hour time-weighted average.

    Is there one standard for all work?

    No. Section 1910.1053 covers general industry and maritime and excludes construction, which is covered by 1926.1153.

    When is medical surveillance required?

    In general industry it applies to employees exposed at or above the action level for 30 or more days a year. In construction it applies to employees required to use a respirator for 30 or more days a year.

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