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Toolbox talk · 10 min · Health & Ergonomics

Silica Dust Control

Hazards: Respirable crystalline silica dust from cutting, grinding, drilling and chipping · Silicosis, lung cancer, COPD and kidney disease · Re-suspended dust from dry sweeping and compressed air

Why it matters

About 2.3 million people in the U.S. are exposed to silica at work, according to OSHA. The dust that matters is invisible: respirable crystalline silica is at least 100 times smaller than beach sand, and it comes off every cut, grind, drill and chip in concrete, block, brick, mortar and stone. It causes silicosis, which has no cure, plus lung cancer, COPD and kidney disease. The limit is 50 micrograms per cubic meter over eight hours (29 CFR 1926.1153(d)(1)) — a number you cannot see or smell.

Key points

  • Work off Table 1, or off air sampling. There is no third option: 1926.1153(c)(1) says you fully and properly implement the controls Table 1 lists for the task, or you assess the exposure under paragraph (d).
  • Keep water on the blade the whole cut. Table 1 wants a system that continuously feeds the blade, and (c)(2)(ii) wants enough flow to minimize visible dust. A trickle that quits mid-cut is not the control.
  • A shroud is only a control with the right vacuum. Table 1 calls for a filter of 99% efficiency or better with a filter-cleaning mechanism, and for grinders, 25 cfm of airflow per inch of wheel diameter.
  • Indoors changes the answer. A handheld power saw outdoors needs no respirator up to four hours; the same saw indoors needs an APF 10 respirator all shift, plus exhaust under (c)(2)(i).
  • Add your Table 1 tasks together. Under (c)(3), if all Table 1 work in the shift passes four hours, every task uses the over-four-hours respirator. Tuckpointing over four hours is the one APF 25 job in the table.
  • No dry sweeping, no compressed air. Paragraph (f) allows those only where wet sweeping, HEPA vacuuming or another low-exposure method is not feasible.
  • A respirator only protects inside a program. 29 CFR 1910.134 means medical evaluation, a passing fit test and training first. Facial hair on the sealing surface cancels the protection factor.

Do / Don't

Do

  • Fill the water tank before the first cut, and watch the stream during the cut.
  • Empty the vacuum and change the filter on schedule.
  • Say so when a task moves indoors, and get the respirator call updated.
  • Wear the respirator your fit test was done on, clean shaven at the seal.

Don't

  • Don't run a dry cut "just for a couple of pieces."
  • Don't pull the shroud off to see the wheel better.
  • Don't grab a broom or an air hose to clean concrete dust.
  • Don't treat a dust mask from the gang box as respiratory protection.

Quick site check

  • Every saw and grinder on masonry today: water running, or shroud with a working vacuum?
  • Anyone over four hours of Table 1 work, and does their respirator match that column?
  • Any tuckpointing scheduled, and is an APF 25 respirator on site for it?
  • Can someone show you the written exposure control plan for this job?
Discussion — ask the crew
  1. Which of the tasks we are running today is on Table 1, and what does Table 1 say the control is?
  2. Who checks that the water is actually reaching the blade once the saw is in the cut, not just when it is idling?
  3. We had a task move indoors last week. Did anyone change the respirator call when it did?
  4. How do we clean up at the end of the shift right now, and what would it take to stop using a broom?
  5. Add up your own Table 1 time on a heavy day. Are you over four hours?
Refs: 29 CFR 1926.1153 — Respirable Crystalline Silica (construction), Table 1 and paragraphs (c) through (i) · OSHA — Silica, Crystalline safety and health topic page (about 2.3 million people exposed at work) · 29 CFR 1910.134 — Respiratory protection: assigned protection factors and program requirementsSign-in sheet included in the printed version

Frequently asked questions

50 micrograms per cubic meter of air as an 8-hour time-weighted average, under 29 CFR 1926.1153(d)(1) in construction and 1910.1053(c) in general industry. The action level is 25 micrograms per cubic meter.

Not if you follow Table 1. Paragraph 1926.1153(c)(1) lets you fully and properly implement the engineering controls, work practices and respiratory protection Table 1 specifies for the task. If you do not, or the task is not on Table 1, you go to paragraph (d) and assess the exposure.

Table 1 gives two respirator answers for many tasks: one for four hours or less per shift, one for more than four hours. Under 1926.1153(c)(3), when a worker does several Table 1 tasks in a shift you add the time together and use the over-four-hours column if the total passes four hours.

Handheld grinders used for mortar removal, that is tuckpointing. Table 1 item (xi) calls for a respirator with an assigned protection factor of 10 at four hours or less, and APF 25 above four hours, with the shroud and dust collection system in place.

1926.1153(f)(1) does not allow dry sweeping or dry brushing where it could add to silica exposure unless wet sweeping, HEPA-filtered vacuuming or another method that minimizes exposure is not feasible. Compressed air for cleaning is restricted the same way under (f)(2).

Under 1926.1153(h)(1)(i) the employer must make medical surveillance available at no cost for each employee who will be required to use a respirator for 30 or more days per year under the silica standard.

Sources & references

Content checked against these sources — last reviewed August 28, 2026.

Results are estimates for planning purposes and do not replace a competent person's evaluation or an engineer's design. Follow the OSHA standards that apply to your work and your employer's written program.

By — Editorial team of SteelToeTools.com (published by LSEA SAS) Updated