1910.94(a)(3)(i): Ventilation for Blast-Cleaning Enclosures
Employers must exhaust ventilate blast-cleaning enclosures to maintain a continuous inward air flow at all openings during blasting, with baffles so no visible spurts of dust escape. Exhaust must clear dusty air promptly, the blast must be off and exhaust run before opening, observation windows need screened safety glass with hard deep-cutting abrasives, and access-opening baffles must be inspected and replaced.
Key takeaways
- 1910.94(a)(3)(i) is part of OSHA's general industry standards (29 CFR Part 1910, Subpart G).
- OSHA cited it 15 times in the last 3 years, in 12 inspections, with $145,359 in current penalties.
- Most citations: MA (3), ID (3), PA (2).
- Related part: 1910.94(a) Abrasive blasting (65 citations).
- Free 5-minute toolbox talk for your crew below.
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In this article
What this rule covers
29 CFR 1910.94(a)(3)(i) is one requirement inside 1910.94 Ventilation, an OSHA general industry standard (Part 1910, Subpart G). 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
(i) Blast-cleaning enclosures shall be exhaust ventilated in such a way that a continuous inward flow of air will be maintained at all openings in the enclosure during the blasting operation. 15 citations
(a) All air inlets and access openings shall be baffled or so arranged that by the combination of inward air flow and baffling the escape of abrasive or dust particules into an adjacent work area will be minimized and visible spurts of dust will not be observed.
(b) The rate of exhaust shall be sufficient to provide prompt clearance of the dust-laden air within the enclosure after the cessation of blasting.
(c) Before the enclosure is opened, the blast shall be turned off and the exhaust system shall be run for a sufficient period of time to remove the dusty air within the enclosure.
(d) Safety glass protected by screening shall be used in observation windows, where hard deep-cutting abrasives are used.
(e) Slit abrasive-resistant baffles shall be installed in multiple sets at all small access openings where dust might escape, and shall be inspected regularly and replaced when needed.
(1) Doors shall be flanged and tight when closed.
(2) Doors on blast-cleaning rooms shall be operable from both inside and outside, except that where there is a small operator access door, the large work access door may be closed or opened from the outside only.
Source: eCFR, text current as of 2026-10-15. Read all of 1910.94.
Export the list: 12 inspections cited 1910.94(a)(3)(i) in the last 3 years, with employer, location, penalty and date.
Purple Belt, $59/moWhere and how often it was cited
| Year | Citations |
|---|---|
| 2023 | 2 |
| 2024 | 6 |
| 2025 | 4 |
| 2026 | 3 |
Top states: MA (3), ID (3), PA (2), OK (2), WI (2)
Largest penalties
| Employer | Location | Penalty for this rule |
|---|---|---|
| VTCU, CORP. | POCATELLO, ID | $101,672 |
| SUN ENERGY SERVICES LLC | ZELIENOPLE, PA | $10,775 |
| VTCU, CORP. | POCATELLO, ID | $9,507 |
| BLACK BAY VENTURES VI, LLC | PALMER, MA | $6,312 |
| LASER SPECIALTIES INC. | TULSA, OK | $5,808 |
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A 5-minute crew talk on 1910.94(a)(3)(i), plus alerts when this rule changes. Free.
OSHA interpretation letters
None exist. OSHA has not published a letter of interpretation for 1910.94(a)(3)(i).
Related parts of this rule
- 1910.94(a) Abrasive blasting 65 citations
- 1910.94(a)(4) Exhaust ventilation systems 19 citations
- 1910.94(a)(5) Personal protective equipment 18 citations
- 1910.94(a)(3) Blast-cleaning enclosures 15 citations
- 1910.94(a)(4)(i) 14 citations
- 1910.94(a)(5)(ii) 4 citations
- 1910.94(a)(5)(i) 4 citations
- 1910.94(a)(2) Dust hazards from abrasive blasting 3 citations
- 1910.94(a)(1) Definitions applicable to this paragraph 1 citations
- 1910.94(a)(1)(ii) Abrasive-blasting respirator
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Frequently asked questions
What should you never see at enclosure openings?
Visible spurts of dust.
When are screened safety glass windows required?
In observation windows where hard deep-cutting abrasives are used.
How must baffles be maintained?
Slit abrasive-resistant baffles at small access openings must be inspected regularly and replaced when needed.
About this page
Sources
- 29 CFR 1910.94 (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 2026-11-06
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.