General Industry (29 CFR 1910)

Permit-Required Confined Spaces

Verified vs OSHA sources · 2026-10-05

29 CFR 1910.146

29 CFR 1910.146 governs permit-required confined spaces in general industry: employers must evaluate their spaces, and for those with atmospheric or other serious hazards, use a permit system with atmospheric testing, an attendant, an entry supervisor, and rescue arrangements before anyone enters. Not every confined space is permit-required, but every one must be evaluated.

29 CFR 1910.146 at a glance

What it requires: Identify and safely control entry into permit-required confined spaces
Acceptable atmosphere: Oxygen 19.5–23.5%; flammables below 10% of the LFL; toxics below their PEL
Key duty: Evaluate spaces, and for permit spaces: test the air, issue an entry permit, and post an attendant
Enforcement: The permit-space rule for general industry
Max penalty (2026): $16,550 per serious violation; $165,514 per willful
The #1 confusion: Not every confined space is 'permit-required': the hazards are what make it one

What 29 CFR 1910.146 requires (plain English)

29 CFR 1910.146 governs permit-required confined spaces in general industry: enclosed spaces like tanks, vessels, silos, vaults, pits, and sewers that are large enough to enter, have limited means of entry and exit, and are not designed for continuous occupancy. Confined spaces are disproportionately deadly: they routinely kill more than one worker at a time, because would-be rescuers rush in and are overcome by the same atmosphere that felled the first entrant. The standard's entire purpose is to force testing, isolation, and rescue planning BEFORE anyone goes in.

The first duty is evaluation: the employer must survey the workplace to determine whether any spaces are permit-required confined spaces (PRCS). A space becomes "permit-required" when it has one or more serious hazards: a hazardous atmosphere, a material that could engulf an entrant, an internal configuration that could trap or asphyxiate, or any other recognized serious hazard. For a PRCS, the employer must implement a written permit-space program: test and monitor the atmosphere, isolate energy and hazards, provide ventilation, issue a signed entry permit for each entry, and station an attendant outside who never enters to attempt a rescue.

Acceptable entry conditions are specific: oxygen between 19.5% and 23.5%, flammable gas or vapor below 10% of its lower flammable limit, and toxic contaminants below their permissible exposure limits. Three roles are defined: the authorized entrant, the attendant (who stays outside and monitors), and the entry supervisor (who verifies conditions, signs the permit, and can terminate the entry). Rescue and emergency services must be arranged before entry. In construction, permit-required confined spaces are governed by the parallel standard 29 CFR 1926 Subpart AA.

The regulatory text

“The employer shall evaluate the workplace to determine if any spaces are permit-required confined spaces.”

29 CFR 1910.146(c)(1)

Key facts about 29 CFR 1910.146

A confined space is large enough to enter, has limited entry/exit, and is not designed for continuous occupancy.
It becomes PERMIT-required if it has a hazardous atmosphere, engulfment risk, an entrapping configuration, or another recognized serious hazard.
Acceptable atmosphere: oxygen 19.5–23.5%; flammables below 10% of the LFL; toxics below their PEL.
For a permit space: test the atmosphere, isolate hazards, ventilate, and issue a signed entry permit for each entry.
Three roles: authorized entrant, attendant (stays outside, never enters to rescue), and entry supervisor.
Rescue and emergency services must be arranged before entry (1910.146(k)).
Construction permit-required confined spaces are governed by the parallel 29 CFR 1926 Subpart AA.

Scope: who 29 CFR 1910.146 applies to

Regulatory framework: General Industry (29 CFR 1910)
Citation reference: 29 CFR 1910.146
Enforcement status: In force and enforced
Jurisdiction: Federal OSHA (29 State-Plan jurisdictions may be stricter)

State-Plan states (e.g. California, Washington, Michigan) operate OSHA-approved programs that must be at least as effective as federal OSHA and frequently impose higher penalties or additional requirements. Confirm the rule as adopted in your state.

Key requirements of 29 CFR 1910.146

#	Employer obligation
1	Evaluate workplace for confined spaces
2	Develop written permit space program
3	Test atmosphere before and during entry
4	Provide ventilation to control hazardous atmospheres
5	Station an attendant outside each permit space
6	Arrange rescue services before entry begins
7	Issue entry permits for each entry

Summarized from the text of 29 CFR 1910.146. Always read the full regulation for the binding language.

Common Confined Spaces violations

Deficiencies OSHA cites under 29 CFR 1910.146 include the ones below, in no particular order. Distinct deficiencies can be cited as separate items, and each serious item carries up to $16,550 (2026). Broader per-instance stacking exists but is a discretionary, case-by-case OSHA enforcement policy, not an automatic multiplier.

Failing to evaluate the workplace to identify permit-required confined spaces (1910.146(c)(1)).
Entry without atmospheric testing or with an atmosphere outside the acceptable ranges (1910.146(c)(5)/(d)).
No written permit-space program, or no signed entry permit for the entry (1910.146(c)(4)/(e)).
No attendant stationed outside, or the attendant entering to attempt a rescue (1910.146(i)/(k)).
No arranged rescue and emergency services before entry (1910.146(k)).

Not every confined space needs a permit

A frequent and dangerous error is treating 'confined space' and 'permit-required confined space' as the same thing (or assuming neither applies). A CONFINED SPACE is simply large enough to enter, with limited entry/exit, and not designed for continuous occupancy. It becomes a PERMIT-REQUIRED confined space only when it also contains a serious hazard: a hazardous (or potentially hazardous) atmosphere, an engulfment risk, an internal shape that could trap or asphyxiate, or another recognized serious hazard. A non-permit confined space has none of those. The opposite error, assuming a space is 'just a tank' and skipping atmospheric testing, is exactly how confined-space fatalities happen. Evaluate every confined space; test before entry; and never let an untrained rescuer enter.

What OSHA inspectors look for

A compliance officer asks whether the employer evaluated its confined spaces and identified which are permit-required, then checks the entry permits, the atmospheric test results for oxygen, flammables, and toxics, the attendant stationed outside, and the rescue plan.

Example: how a violation is cited

A worker enters a below-grade vault to fix a pump without testing the air and is overcome by an oxygen-deficient atmosphere; a co-worker who goes in to help is overcome too. OSHA can cite 1910.146(d)(5) for entry without testing, (e) for entry without a permit and (k) for having no rescue arranged.

Illustrative example, not a specific OSHA case.

Confined Spaces compliance checklist

Use this to evaluate your compliance with 29 CFR 1910.146. Each item is a key requirement OSHA may verify during an inspection.

Evaluate the workplace and identify all permit-required confined spaces; sign/label them.
Develop a written permit-space program and train entrants, attendants, and entry supervisors.
Before entry, isolate hazards, test and monitor the atmosphere, and ventilate as needed.
Confirm acceptable conditions (O2 19.5–23.5%, flammables <10% LFL, toxics <PEL) and issue a signed entry permit.
Station an attendant outside who maintains contact and never enters to attempt a rescue.
Arrange rescue and emergency services and verify they can respond before entry begins.

2026 penalties for 29 CFR 1910.146

Maximums set by 29 CFR 1903.15(d). 2026 amounts unchanged from 2025 (no CPI adjustment; OMB M-26-11). Not an increase. The 2025 OSHA penalty levels remain in effect for 2026; OSHA made no inflation adjustment for 2026. 29 CFR 1903.15 identifies January 15, 2025 as the effective reference for these amounts, while OSHA's public penalties page currently references penalties assessed after Jan. 15, 2026.

Violation type	Minimum	Maximum	When it applies
Serious	$1,085	$16,550	Substantial probability of death or serious physical harm.
Other-Than-Serious	$0	$16,550	Relates to safety/health but unlikely to cause death or serious harm.
Willful	$11,823	$165,514	Intentional, knowing, or voluntary disregard of the requirement.
Repeated	$4,256	$165,514	A substantially similar violation cited within the last 5 years.
Failure to Abate	None	$16,550/day	up to $16,550 per day; total capped at 30x the daily amount (FOM Ch.6)

A serious violation carries up to $16,550 and a willful or repeat violation up to $165,514, per violation, not per exposed employee. Evaluating the workplace ((c)(1)), the written program ((c)(4)), entry permits ((e), (f)) and rescue ((k)) are separate requirements, so an entry that skips several can produce several items.

Maximums and the willful minimum are set by 29 CFR 1903.15(d); the serious and repeated minimums are OSHA policy floors from its annual penalty adjustment memo. OSHA applies gravity-based and size, good-faith and history reductions (FOM CPL 02-00-164 Ch.6). Estimates only, not legal advice.

The business case for Confined Spaces compliance

Confined spaces kill in ways that give no warning: an oxygen-deficient or toxic atmosphere is invisible, and more than half of confined-space deaths are would-be rescuers who enter unprotected. Atmospheric testing and a rescue plan before entry are what separate a routine job from a multiple-fatality event.

Free compliance tools for 29 CFR 1910.146

Confined Space Permit Generator

Confined Spaces penalties by state

Penalties and enforcement vary by state. State-Plan states may impose higher penalties and additional requirements beyond federal 29 CFR 1910.146.

Alabama Arkansas Colorado Connecticut Delaware District of Columbia

View all 50 states + DC →

Frequently asked questions about 29 CFR 1910.146

What makes a confined space 'permit-required'?

A confined space is large enough to enter, has limited means of entry and exit, and is not designed for continuous occupancy. It becomes a permit-required confined space when it also has one or more serious hazards: a hazardous (or potentially hazardous) atmosphere, a material that could engulf an entrant, an internal configuration that could trap or asphyxiate, or any other recognized serious safety or health hazard. If none of those are present, it is a non-permit confined space.

What are acceptable atmospheric conditions for confined space entry?

Oxygen concentration must be between 19.5% and 23.5%; flammable gases or vapors must be below 10% of the lower flammable limit (LFL); and toxic contaminants must be below their permissible exposure limits (PELs). The atmosphere must be tested before entry (generally in the order oxygen, then flammables, then toxics) and monitored as conditions require. If any parameter is outside the acceptable range, entry is prohibited until the space is ventilated or otherwise corrected.

What are the roles in a confined space entry?

Three roles are defined. The authorized entrant enters the space and must know the hazards and exit on an alarm or order. The attendant is stationed outside, monitors the entrants and conditions, and summons rescue, but never enters to attempt a rescue. The entry supervisor verifies that acceptable conditions exist, signs the permit to authorize entry, and terminates the entry and cancels the permit when the work is done or a prohibited condition arises.

Does 1910.146 apply to construction?

No: construction has its own parallel standard. General industry permit-required confined spaces are governed by 1910.146, while construction permit-required confined spaces are governed by 29 CFR 1926 Subpart AA (1926.1200–1213), added in 2015. The construction standard mirrors the permit-space program approach but adds requirements for coordinating multiple employers working on or near the same confined space: common on construction sites.

Regulatory history of 29 CFR 1910.146

OSHA issued the general-industry permit-required confined spaces standard (1910.146) in 1993, establishing the permit-space program framework. In 2015, OSHA added a parallel construction standard: 29 CFR 1926 Subpart AA (1926.1200–1213): that mirrors the program approach while adding multi-employer coordination duties for construction sites.

Related glossary terms

Key terms that appear in 29 CFR 1910.146, each with a full plain-English explainer.

Confined Space Confined Space Entry Permit Atmospheric Testing IDLH Simple Asphyxiant

Related guides & articles

Confined Space Entry: Permit-Required OSHA Guide

Related OSHA standards

29 CFR 1926.800

Underground Construction

29 CFR 1926.1201

Confined Spaces (Construction) Scope

29 CFR 1926.1203

Confined Spaces General (Construction)

29 CFR 1926.1204

Permit Spaces (Construction)

Primary sources

OSHA figures on this page are imported from HazComFast's verified regulatory module (verified 2026-10-05 against eCFR, OSHA.gov, and the Federal Register).

This page is an educational summary, not legal advice. OSHA standards and penalty amounts change; confirm requirements against the current regulation and your applicable State-Plan before acting.

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