Table 1 of the OSHA silica standard is a deal. For eighteen named construction tasks, OSHA has already worked out an acceptable control — and if you implement it fully and properly, you never have to sample the air for that task. Get any part of the specified method wrong and the deal is off: you are back on the exposure assessment route, with a 50 µg/m³ permissible exposure limit to prove you are under.
Two routes, and you choose per task
29 CFR 1926.1153 applies to all occupational exposures to respirable crystalline silica in construction work, except where employee exposure will remain below 25 µg/m³ as an 8-hour TWA under any foreseeable conditions. Above that, you pick a route — and you can pick a different one for each task on the job.
| Table 1 — paragraph (c) | Alternative methods — paragraph (d) | |
|---|---|---|
| What you do | Implement the specified engineering control, work practice and respirator for the task | Assess exposure, then control it with engineering and work practice controls |
| Air monitoring | Not required for that task | Performance option or scheduled monitoring option, (d)(2) |
| Exposure limit to prove | None to prove — the method is the compliance | 50 µg/m³ 8-hour TWA, (d)(1) |
| Respirator selection | Read off the table; (e)(3) deems you compliant with 1910.134(d)(1)(iii) and (d)(3) | Based on the assessed exposure |
| Applies to | Only the eighteen listed tasks | Everything else, and any Table 1 task where the method is not fully implemented |
Paragraph (c)(1) states the bargain directly: “For each employee engaged in a task identified on Table 1, the employer shall fully and properly implement the engineering controls, work practices, and respiratory protection specified for the task on Table 1, unless the employer assesses and limits the exposure of the employee to respirable crystalline silica in accordance with paragraph (d) of this section.”
The eighteen tasks and what each one needs
The control column below is shortened to keep the table readable. The wording in the standard is what governs, and it is specific — filter efficiencies, airflow figures, whether water is fed to the blade or sprayed at the point of impact. Pull the exact text for your task with the Table 1 lookup.
| Task | Specified control (short) | ≤ 4 h | > 4 h |
|---|---|---|---|
| (i) Stationary masonry saws | Integrated water to the blade | None | None |
| (ii) Handheld power saws, any blade | Integrated water to the blade | None outdoors APF 10 indoors | APF 10 APF 10 indoors |
| (iii) Handheld power saws, fiber-cement board (blade ≤ 8 in) | Dust collection, filter ≥ 99% — outdoors only | None | None |
| (iv) Walk-behind saws | Integrated water to the blade | None outdoors APF 10 indoors | None outdoors APF 10 indoors |
| (v) Drivable saws | Integrated water to the blade — outdoors only | None | None |
| (vi) Rig-mounted core saws or drills | Integrated water to the cutting surface | None | None |
| (vii) Handheld and stand-mounted drills | Shroud or cowling with dust collection; HEPA vacuum for holes | None | None |
| (viii) Dowel drilling rigs for concrete | Shroud with dust collection; HEPA vacuum for holes — outdoors only | APF 10 | APF 10 |
| (ix) Vehicle-mounted drilling rigs, rock and concrete | Dust collection with close capture hood or enclosed cab with water | None | None |
| (x) Jackhammers and handheld chipping tools | Water at the point of impact or shroud with dust collection | None outdoors APF 10 indoors | APF 10 APF 10 indoors |
| (xi) Handheld grinders for mortar removal (tuckpointing) | Shroud with dust collection, ≥ 25 cfm per inch of wheel | APF 10 | APF 25 |
| (xii) Handheld grinders, other uses | Integrated water (outdoors only) or shroud with dust collection | None | None outdoors APF 10 indoors |
| (xiii) Walk-behind milling machines and floor grinders | Integrated water or manufacturer's dust collection; HEPA vacuum between passes indoors | None | None |
| (xiv) Small drivable milling machines (< half-lane) | Water sprays with a surfactant | None | None |
| (xv) Large drivable milling machines (half-lane and larger) | Drum exhaust ventilation with water sprays or water spray with surfactant for cuts ≤ 4 in | None | None |
| (xvi) Crushing machines | Water spray at every dust point; ventilated booth or remote station | None | None |
| (xvii) Heavy equipment abrading or fracturing silica materials, or demolition | Enclosed cab; water or suppressants when anyone works outside the cab | None | None |
| (xviii) Heavy equipment grading and excavating | Water or dust suppressants or enclosed cab when the operator is alone | None | None |
Two things jump out of that table. Most entries require no respirator at all when the engineering control is genuinely running — the water and the dust collector are doing the work. And tuckpointing is the only APF 25 task in the standard, because grinding mortar out of a joint generates more respirable silica than anything else a crew does by hand.
The four-hour rule is a shift total
This is the single most misread line in the standard. 1926.1153(c)(3):
Where an employee performs more than one task on Table 1 during the course of a shift, and the total duration of all tasks combined is more than four hours, the required respiratory protection for each task is the respiratory protection specified for more than four hours per shift. If the total duration of all tasks on Table 1 combined is less than four hours, the required respiratory protection for each task is the respiratory protection specified for less than four hours per shift.29 CFR 1926.1153(c)(3)
Worked through: a mason spends two hours tuckpointing and three hours cutting block with a handheld saw outdoors. Read task by task, both sit under four hours — APF 10 for the grinder, none for the saw. Read the way the standard says, the combined total is five hours, so both tasks take the “more than four hours” column: APF 25 for the tuckpointing and APF 10 for the saw.
“Fully and properly” is where the deal breaks
Paragraph (d) opens by naming its own scope: for tasks not listed in Table 1, or where the employer does not fully and properly implement the engineering controls, work practices, and respiratory protection described in Table 1. That second clause is the trap. Common ways a crew falls out of Table 1 without noticing:
- The water is off, or it is a trickle. (c)(2)(ii) requires water applied at flow rates sufficient to minimize the release of visible dust. Visible dust means the method is not working.
- The vacuum is unplugged, full, or the wrong one. Most entries name a filter efficiency of 99% or greater and, for several tools, the airflow the tool manufacturer recommends plus a filter-cleaning mechanism.
- The shroud has been taken off. A grinder without its shroud is not doing entry (xi) or (xii).
- An outdoors-only method used indoors. Entries (iii), (v), (viii) and the water method of (xii) have no Table 1 option in an enclosed area.
- No exhaust indoors. (c)(2)(i) requires a means of exhaust as needed to minimize the accumulation of visible airborne dust for any Table 1 task performed indoors or in an enclosed area.
- The cab is not a cab. Where the method relies on an enclosed cab or booth, (c)(2)(iii) requires it to be kept as free as practicable from settled dust, with working door seals and closing mechanisms, gaskets and seals in good condition, positive pressure from continuously delivered fresh air, intake air filtered at 95% efficiency in the 0.3–10.0 µm range (MERV-16 or better), and heating and cooling.
When any of those is true, the task is on the paragraph (d) route for as long as it stays true: assess the exposure, control it to the 50 µg/m³ PEL with engineering and work practice controls, and supplement with respirators only where those controls are not sufficient.
What Table 1 does not excuse
Following Table 1 buys you exactly one thing: no exposure assessment for those tasks. Everything else in the standard still applies.
| Obligation | What it requires | ¶ |
|---|---|---|
| Written exposure control plan | Tasks, controls and respirators per task, housekeeping, access restriction; reviewed at least annually; a competent person designated to make frequent and regular inspections | (g) |
| Housekeeping | No dry sweeping or dry brushing, and no compressed air on clothing or surfaces, where either could contribute to exposure — with narrow feasibility exceptions | (f) |
| Respiratory protection program | A full 29 CFR 1910.134 program wherever a respirator is required — written program, medical evaluation, fit testing, training | (e)(2) |
| Medical surveillance | Made available at no cost to each employee required to use a respirator 30 or more days per year | (h)(1)(i) |
| Hazard communication and training | Silica in the HazCom program, addressing cancer, lung effects, immune system effects and kidney effects; six specific training topics | (i) |
| Recordkeeping | Air monitoring data and objective data, maintained per 29 CFR 1910.1020 | (j) |
The plan is the one most often missing. Build it around the four elements the standard actually lists with the silica written exposure control plan generator, and document the respirator choice for each task in a PPE hazard assessment.
Five mistakes that cost the Table 1 protection
- Reading the four hours task by task. It is the combined shift total, every time.
- Assuming “no respirator” means “no controls”. The “None” entries are earned by the water or the dust collector. Turn it off and you have neither.
- Using an outdoors-only method inside. Four entries have no indoor option at all.
- Skipping the written plan because you follow Table 1. Paragraph (g) does not care which route you took.
- Handing out a half-mask without the program behind it. A respirator required by this standard drags in all of 1910.134 — medical evaluation, fit test, training.
Bottom line
- Eighteen tasks, each with a specified control and a respirator column for ≤ 4 h and > 4 h.
- Implement the method fully and properly and you skip the exposure assessment for that task — that is the entire benefit.
- The four hours is the combined total of all Table 1 tasks in the shift.
- Tuckpointing above four hours is the only APF 25 in the table.
- Written plan, housekeeping, training, medical surveillance and records apply either way.