1926.1153(d)(2)(iii): Scheduled Monitoring for Silica Exposure
Under the scheduled monitoring option, employers must do initial personal breathing zone sampling to find 8-hour TWA silica exposure for each shift, job and work area; representative sampling must include those expected to have the highest exposure. Monitoring repeats within six months if exposure is at or above the action level but at or below the PEL, within three months if above the PEL, and may stop once results are below the action level as set out in the rule.
Key takeaways
- 1926.1153(d)(2)(iii) is part of OSHA's construction standards (29 CFR Part 1926, Subpart Z).
- OSHA cited it 10 times in the last 3 years, in 10 inspections, with $22,762 in current penalties.
- Most citations: IN (1), AZ (1), ME (1).
- Related part: 1926.1153(d) Alternative exposure control methods (694 citations).
- Free 5-minute toolbox talk for your crew below.
In this article
What this rule covers
29 CFR 1926.1153(d)(2)(iii) ("Scheduled monitoring option") is one requirement inside 1926.1153 Respirable crystalline silica, an OSHA construction standard (Part 1926, Subpart Z). It includes 5 sub-paragraphs. The official text below is copied word for word from the Electronic Code of Federal Regulations (eCFR). The numbers, injury cases and training on this page show how OSHA enforces it on real job sites.
Official text
(iii) Scheduled monitoring option. 10 citations
(A) The employer shall 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. Where several employees perform the same tasks on the same shift and in the same work area, the employer may sample a representative fraction of these employees in order to meet this requirement. In representative sampling, the employer shall sample the employee(s) who are expected to have the highest exposure to respirable crystalline silica. 6 citations
(B) If initial monitoring indicates that employee exposures are below the action level, the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring. Open (d)(2)(iii)(b)
(C) Where the most recent exposure monitoring indicates that employee exposures are at or above the action level but at or below the PEL, the employer shall repeat such monitoring within six months of the most recent monitoring.
(D) Where the most recent exposure monitoring indicates that employee exposures are above the PEL, the employer shall repeat such monitoring within three months of the most recent monitoring. 4 citations
(E) Where the most recent (non-initial) exposure monitoring indicates that employee exposures are below the action level, the employer shall repeat such monitoring within six months of the most recent monitoring until two consecutive measurements, taken seven or more days apart, are below the action level, at which time the employer may discontinue monitoring for those employees whose exposures are represented by such monitoring, except as otherwise provided in paragraph (d)(2)(iv) of this section. Open (d)(2)(iii)(e)
Source: eCFR, text current as of 2026-10-15. Read all of 1926.1153.
Where and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 2 |
| 2024 | 4 |
| 2025 | 2 |
| 2026 | 2 |
Top states: IN (1), AZ (1), ME (1), NJ (1), MN (1)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| MOHAWK NORTHEAST, INC. | BRIDGEPORT, CT | $9,847 |
| 107691 - ASTECH LLC | COTTAGE GROVE, MN | $4,800 |
| MORTON TREESCAPE LLC | OGUNQUIT, ME | $4,000 |
| JEFFREY H LANDSCAPING, LLC | ENGLEWOOD, NJ | $2,765 |
| DECORATIVE PAVING CO. | BLOOMINGTON, IN | $1,350 |
Free toolbox talk
A 5-minute crew talk on 1926.1153(d)(2)(iii), plus alerts when this rule changes. Free.
OSHA interpretation letters
- Interim Enforcement Guidance for the Respirable Crystalline Silica in Construction Standard, 29 CFR 1926.1153 (2017-10-19)
Related parts of this rule
- 1926.1153(d) Alternative exposure control methods 694 citations
- 1926.1153(d)(2) Exposure assessment 645 citations
- 1926.1153(d)(2)(i) General 623 citations
- 1926.1153(d)(1) Permissible exposure limit (PEL) 35 citations
- 1926.1153(d)(3) Methods of compliance 14 citations
- 1926.1153(d)(3)(i) Engineering and work practice controls 14 citations
- 1926.1153(d)(2)(vi) Employee notification of assessment results 1 citations
- 1926.1153(d)(2)(iii)(E)
- 1926.1153(d)(2)(iii)(B)
- 1926.1153(d)(2)(v) Methods of sample analysis
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Frequently asked questions
How often must silica monitoring be repeated if exposure is above the PEL?
Within three months of the most recent monitoring.
What if exposure is at or above the action level but at or below the PEL?
Repeat monitoring within six months of the most recent monitoring.
When can monitoring stop?
If initial monitoring is below the action level, or after two consecutive non-initial measurements taken seven or more days apart are below the action level, except as provided in paragraph (d)(2)(iv).
About this page
Sources
- 29 CFR 1926.1153 (eCFR), text current as of 2026-10-15
- U.S. Department of Labor enforcement data: OSHA inspections, citations and accident records, copied nightly; data as of 2026-10-19
3-year window. Federal OSHA only; state-plan rules are not counted. Plain-language text is a summary, not legal advice; the official text controls. Black Belt Safety is not part of OSHA or the Department of Labor.