Last updated September 30, 2026.

This page produces a documented decision on one silica task. The decision is whether objective data shows that exposure stays below the action level, so that the employer does not have to sample the air. The employer must be able to show that the data describes conditions at least as dusty as the employer's own. If the data cannot show that, it cannot be used.

What you need

  • The applicable standard

    Use [29 CFR 1910.1053](https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.1053) for general industry and maritime. Use [29 CFR 1926.1153](https://www.osha.gov/laws-regs/regulations/standardnumber/1926/1926.1153) for construction.

  • A written description of the task

    It must cover the material, process, control methods, work practices and environmental conditions.

  • At least one source of objective data

    Examples are an industry-wide survey, manufacturer data, trade association data, exposure mapping, a composition calculation, or the employer's own earlier sampling.

  • The two thresholds

    The action level is 25 µg/m³ as an 8-hour TWA. The PEL is 50 µg/m³ as an 8-hour TWA.

The steps

  1. Define one task. Name the product or material, the process and the activity. Worked when: the description would let a stranger tell this task apart from every other silica task at the site.

  2. Gather the candidate data. Use the sources OSHA lists on its general industry silica page. Historical air monitoring data counts only if it passes step 3. Worked when: each result is tied to a named material and a named task.

  3. Compare conditions line by line. Check the processes, materials, control methods, work practices and environmental conditions. The data must reflect conditions "closely resembling or with a higher exposure potential than" current operations. Worked when: no condition in the data is less dusty than the task as it is performed now.

  4. Test against 25 µg/m³. Use the conditions most likely to produce the highest exposure. Worked when: the data shows exposure below 25 µg/m³ as an 8-hour TWA "under any foreseeable conditions."

  5. Record the result. Under 1926.1153(j)(2), the record must include the material tested, the source of the data, the testing protocol and results, a description of the process, and other relevant exposure information. Worked when: each of those items is present in writing.

  6. Recheck after any change. If the material, process or controls change, repeat steps 3 and 4. The burden of proof rests on the employer to show that the data describes current exposures. Worked when: the record matches the task as it is performed today.

The facts available for this page do not state how long the objective data record must be kept. The retention period is set in the recordkeeping paragraph of each standard.

Route What it rests on Result
Objective data below the action level Data showing exposure below 25 µg/m³ under any foreseeable conditions General industry: the standard does not apply to that operation, under 1910.1053(a)(2). Construction: certain operations may be exempt from parts of the standard.
Performance option Any combination of air monitoring data and objective data that accurately characterizes exposure Exposure may be placed in a range, for example between the action level and the PEL.
Scheduled monitoring option Personal breathing zone air samples Initial sampling. Repeat every 6 months if at or above 25 µg/m³. Repeat every 3 months if above 50 µg/m³.

If it did not work

No. Data from dissimilar or lower-exposure conditions cannot be relied on. Find data that matches or exceeds the task's conditions, or sample the air.

The exemption is not available for that task. Assess exposure under the performance option or the scheduled monitoring option.

Yes. In an inspection on February 12, 2026, OSHA found that General Shale Brick Inc. (Watsontown Brick Company) had not monitored exposure in all jobs involving silica. The [citation issued August 26, 2026](https://www.osha.gov/news/newsreleases/philadelphia/20260826) proposed $496,528 in penalties for 3 willful, 4 serious, 1 repeat and 1 other-than-serious violations. The company had 15 business days to comply, request an informal conference or contest the findings. The inspection arose under the [silica National Emphasis Program](/osha-silica-national-emphasis-program-and-who-it-targets/).

A task with a complete record is assessed. The record must describe the task as it is performed today. A task without qualifying objective data must be assessed by the monitoring rules described in the OSHA silica standard overview.

When objective data is not available

The monitoring schedule, the PEL and the related requirements for each standard.

Silica standards explained