What must be done under 29 CFR 1910.147 LOTO before any of the §1910.146 PRCS duties apply?

Hazardous-energy isolation under §1910.147 (Lockout/Tagout — The Control of Hazardous Energy) must be completed before any PRCS entry where mechanical, electrical, hydraulic, pneumatic, chemical, or thermal energy could harm an entrant. LOTO is the prerequisite control: an authorized employee applies a lockout device to each energy-isolating device, verifies zero energy by trying to start the machine, and only then authorizes the confined-space entry. Without a verified LOTO application, a PRCS entry is exposed to the same engulfment, electrocution, or mechanical-release hazards that the permit is meant to control. See /manufacturing/loto-safety for the §1910.147 program details that precede PRCS entry.

How does a manufacturer decide whether a space is a permit-required confined space under 29 CFR 1910.146?

§1910.146(a)–(b) classifies a confined space as permit-required when (1) it is large enough for an entrant to bodily enter and perform work, (2) it has limited or restricted entry or exit (e.g. hatches, ladders, top-only entry), and (3) it contains or has the potential to contain a hazardous atmosphere; OR (4) it contains a material that could engulf an entrant; OR (5) it has an internal configuration that could trap or asphyxiate an entrant (inward-converging walls or tapering floors); OR (6) it contains any other recognized serious safety or health hazard. If only the first two criteria are met (no atmospheric or engulfment hazard) the space may be an alternate-entry-permit confined space per §1910.146(c)(5) — but only when the employer can demonstrate that the only hazard is atmospheric, that continuous monitoring with an audible alarm is sufficient, and that no alternate control is needed.

What must a written PRCS program under §1910.146(c) contain, and who authorizes it?

§1910.146(c) requires the employer to identify and evaluate permit spaces before entry, classify each space as PRCS / alternate-entry / non-permit, and implement a written program that (1) identifies the spaces, their hazards, and the measures used to isolate or safeguard entrants; (2) specifies acceptable entry conditions; (3) requires an entry permit before each entry; (4) establishes rescue and emergency services; (5) defines the roles and training of authorized entrants, attendants, and entry supervisors; and (6) coordinates host and contractor duties under §1910.146(j). The program must be available for inspection, signed by a single knowledgeable employer representative, and reviewed at least annually to address any canceled-entry deficiencies, incorrect rescues, or observed program deviations identified during operation.

What are the required elements of a §1910.146(d) entry permit?

§1910.146(d) requires the entry permit to identify (1) the permit space, (2) the purpose of the entry, (3) the date and authorized duration, (4) the authorized entrants by name, (5) the personnel serving as attendants and the entry supervisor, (6) the hazards of the space, (7) the measures used to isolate the space and to safeguard entrants (LOTO, ventilation, PPE), (8) the acceptable entry conditions and the atmospheric test results (oxygen, flammability, toxicity), (9) the rescue and emergency services to be summoned and the means to summon them, (10) the communication procedures used by entrants and attendants, and (11) the post-entry review / cancellation. The entry supervisor signs the permit before entry begins, hangs it at the entry point during the entry, and cancels it when the work is complete or when a condition outside the permit develops.

How is atmospheric testing under §1910.146(e) performed, and in what order?

§1910.146(e) requires atmospheric testing with a calibrated instrument in this order: oxygen concentration first (acceptable entry range 19.5%–23.5%), then flammable gases or vapors (acceptable less than 10% of the Lower Explosive Limit), then toxic substances known or suspected to be present (each below its permissible exposure limit or other applicable limit). Testing must be performed before any entrant enters the space, and atmospheric conditions must be continuously or periodically monitored as dictated by the permit. Ventilation (§1910.146(f)) sufficient to maintain acceptable entry conditions is required whenever feasible; forced-air ventilation alone does not substitute for verified atmospheric testing. Communication between the attendant and entrants under §1910.146(g) uses voice, visual, radio, or other effective means consistent with the §1910.134(d)(3) voice/visual/radio rules where applicable.

What does §1910.146(h) require for rescue and emergency services, and how often must rescue training happen?

§1910.146(h) requires the employer to designate a rescue service that is trained, equipped, and proficient in permitted-space rescue — either an on-site rescue team or a contracted rescue service that meets appendix F. The rescue service must be able to reach the entrant within the time window the entry supervisor determines is required by the space hazards (often minutes for an IDLH engulfment hazard). Each rescuer must be certified in CPR and first aid, must maintain a minimum one-entry-per-rescuer staffing model (no shared SCBA or single-rescuer high-angle entry), and must train on permitted-space rescue at least once every 12 months — in the same or similar permit spaces, using the same rescue techniques the entry is expected to require.

What are the most-cited 29 CFR 1910.146 sections in FY2024?

Most-cited §1910.146 subparagraphs cluster around (c)(1) missing or unsigned written PRCS program, (c)(4) no identification/evaluation of permit-required spaces, (c)(7) deficient training of entrants/attendants/entry supervisors, (d) incomplete or missing entry permit, (e)(1) atmospheric testing omitted or performed in the wrong order, (f) inadequate ventilation or unguarded mechanical hazards inside the space, and (h) rescue service not verified within the entry window. A single PRCS entry that triggered a fatality has historically stacked (c)(4)/(d)/(e)(1)/(h)(2)/(k)(2) citations in one event, with willful or repeat exposure up to $161,323 per cited subparagraph.

Manufacturing Safety | 29 CFR 1910.146

Permit-Required Confined Space for Manufacturing (29 CFR 1910.146) (2025)

29 CFR 1910.146 — the Permit-Required Confined Spaces standard — requires every general-industry manufacturer whose employees enter a confined space that contains or has the potential to contain a hazardous atmosphere, an engulfment hazard, a configuration trap, or any other recognized serious safety or health hazard to run a written PRCS program: a documented decision tree classifying every space, a single knowledgeable employer representative signing the program, a worksite-specific entry permit posted at the entry point for every entry, atmospheric testing performed in the required order with a calibrated four-gas monitor, a verified LOTO prerequisite under §1910.147, an on-site or contracted rescue service that can respond within the entry-supervisor-defined window, separately trained authorized entrants / attendants / entry supervisors, host-contractor coordination, and a record trail that satisfies §1910.1020. Any plant with tanks, vessels, pits, sumps, sewers, boilers, digesters, grain bins, or any top-only-entry work area must comply — and the citation exposure runs up to $161,323 per violation.

29 CFR 1910.146

Multiple §1910.146 Citations / Entry

Updated for 2025

Why It Matters

Permit-required confined spaces are the deadliest recurring exposure in general-industry manufacturing

OSHA’s enforcement data and the Bureau of Labor Statistics Census of Fatal Occupational Injuries consistently identify confined-space incidents as one of the top recurring fatality profiles in general industry. The pattern is well known and almost entirely preventable: an employer skips the decision tree and classifies a permit-required space as a non-permit space, an entry is performed without a signed entry permit, atmospheric testing is omitted or performed in the wrong order, the attendant has duties that pull them away from the entry, the rescue service cannot meet the entry-supervisor-defined summon window, a would-be rescuer dies alongside the original entrant, LOTO precedes entry only in the paperwork and not in the field isolation, the host receives no pre-entry information exchange with a contractor, or the training records cannot show that the entrants and attendants were trained on this specific space. The fatality pathway stacks an entry hazard with a delayed rescue — and the regulatory pathway stacks (c)/(d)/(e)/(h)/(k) citations in one event.

29 CFR 1910.146 was written to consolidate that risk into a single program: scope and the PRCS decision tree in §1910.146(a)–(b); the written PRCS program in §1910.146(c); the entry permit in §1910.146(d); atmospheric testing in §1910.146(e); ventilation in §1910.146(f); communication and attendant duties in §1910.146(g); rescue and emergency services in §1910.146(h); training in §1910.146(i); contractor coordination in §1910.146(j); and recordkeeping in §1910.146(k) (in conjunction with §1910.1020). A well-run PRCS program tracks every space, every reclassification, every canceled permit, every atmospheric test, every attendant assignment, every rescue practice, every training cycle, and every host-contractor coordination event — and ties directly to the OSHA 300, 300A, and 301 entries when a confined-space incident occurs.

~60/yr

workers estimated to be killed in permit-required confined-space incidents in any given audit cycle (BLS Census of Fatal Occupational Injuries)

5–10

§1910.146 subparagraph citations that stack on a single deficient PRCS event — typically (c)(4)/(d)/(e)(1)/(h)/(k) — with willful exposure up to $161,323 per cited subparagraph

29 CFR 1910.146 — Sections That Carry the Citations

Six sub-paragraphs of §1910.146 that govern a complete PRCS program

The §1910.146 standard reads like a tightly stacked rulebook — every subparagraph is a citation trigger, and a deficient PRCS entry can stack citations across multiple subparagraphs in one event. These six subparagraphs cover the program from scope and the decision tree through the written program, the entry permit, atmospheric testing and ventilation, rescue and emergency services, training, contractor coordination, and recordkeeping.

29 CFR 1910.146(a)–(b)

Scope, Applicability & the PRCS Decision Tree

§1910.146(a)–(b) defines the permit-required confined space (PRCS) by the AND/OR combination of (1) large enough that an entrant can bodily enter and perform work, (2) limited or restricted means of entry or exit, and (3) not designed for continuous human occupancy. A space is permit-required if it also contains or has the potential to contain a hazardous atmosphere; OR a material that could engulf an entrant; OR an internal configuration (inward-converging walls, tapering floor) that could trap or asphyxiate an entrant; OR any other recognized serious safety or health hazard. The employer must walk the decision tree for every space, document the classification, and re-evaluate whenever a process change introduces a new hazard. A space with no atmospheric, engulfment, or entanglement hazard may be reclassified as a non-permit space per §1910.146(c)(7).

29 CFR 1910.146(c)

Written Permit-Required Confined Space Program

§1910.146(c) requires a written PRCS program covering identification and evaluation of permit spaces; acceptable entry conditions; the measures used to isolate the space and to safeguard entrants; the entry permit; rescue and emergency services; the roles and training of authorized entrants, attendants, and entry supervisors; and contractor coordination under §1910.146(j). The program is signed by a single knowledgeable employer representative, available to all entrants and contractors at the jobsite for review, and reviewed annually — and updated when a canceled-entry event reveals a deficiency, when an unauthorized rescue reveals a training gap, or when new hazards are introduced to an existing permit space. Reclassification to a non-permit space under §1910.146(c)(7) requires a written certification that all hazards have been eliminated and that the basis for the elimination is documented for each space.

29 CFR 1910.146(d)

Entry Permit

§1910.146(d) requires an entry permit to be completed and approved by the entry supervisor before any entrant enters a permit space, and to be posted at the entry point during the entry. The permit identifies the permit space, the purpose of the entry, the date and authorized duration, the authorized entrants by name, the attendants and entry supervisor, the hazards of the space, the measures used to isolate the space and to control the hazards, the atmospheric test results, the rescue procedures and summon method, the communication procedures, and the cancellation criteria. The entry supervisor cancels the permit when the work is complete or when a condition outside the permit develops, and conducts the post-entry review per appendix C to capture lessons that feed the next permit, the next training, and the next annual program review.

29 CFR 1910.146(e)–(g)

Atmospheric Testing, Ventilation & Communication

§1910.146(e) requires atmospheric testing — oxygen (19.5%–23.5%), flammability (below 10% of LEL), and toxicity (below the PEL or other applicable limit) for any known or suspected contaminant — performed in that order with a calibrated four-gas monitor before any entrant enters the space. Acceptable entry conditions must be verified before entry and maintained continuously or by periodic monitoring as required by the permit. §1910.146(f) requires adequate ventilation whenever feasible to maintain the acceptable entry conditions. §1910.146(g) requires the attendant to maintain effective communication with each entrant — voice, visual, radio, or other means — and to continuously monitor the entry from outside the space, summoning rescue at the first sign of an out-of-permit condition.

29 CFR 1910.146(h)

Rescue & Emergency Services

§1910.146(h) requires the employer to evaluate a prospective rescuer’s ability to respond to a summoning within the entry-supervisor-defined rescue window. The rescue service must be trained and equipped for permitted-space rescue — including the same or similar space, the same configurations, and the same hazards — and meet the appendix F criteria. Each rescuer is CPR/first-aid certified, and rescues are staffed at a minimum of one-entry-per-rescuer to avoid shared SCBA and single-rescuer high-angle entries. Rescue training must occur at least annually, either through an actual permitted-space rescue or a representative practice rescue in a space that mirrors the worst-case configuration and atmospheric hazard the employer expects to encounter.

29 CFR 1910.146(i)–(k)

Training, Contractor Coordination & Recordkeeping

§1910.146(i) requires the employer to provide training to all authorized entrants, attendants, and entry supervisors sufficient to perform their duties under §1910.146. The employer provides additional training whenever (1) there is a change in operations that present new hazards, (2) inadequacies in an employee’s knowledge or use of the program are observed, or (3) deviations from the program or deficiencies in the rescue plan are identified. §1910.146(j) requires host-contractor coordination — host pre-entry information exchange (hazards, prior permits, rescue service), debrief on procedures and any newly discovered hazards, and a coordinated entry program where responsibilities are not duplicated or omitted. §1910.146(k) and §1910.1020 govern recordkeeping — canceled entry permits retained for at least one year; medical/exposure records retained per §1910.1020; training records retained per the agency’s standard and made available to entrants and contractors.

2025 OSHA §1910.146 citation penalties

OSHA adjusts its civil penalty amounts annually for inflation under the Federal Civil Penalties Inflation Adjustment Act. As of January 2025:

Violation Type	Maximum Penalty Per Citation	Typical Trigger
Willful or Repeat	$161,323	Manufacturer knowingly entered a permit-required confined space without completing the entry permit, knowingly skipped atmospheric testing in the required order, knowingly assigned a non-trained attendant or non-trained entrants, knowingly relied on a rescue service that could not meet the entry-supervisor-defined summon window, or knowingly sent a contractor into a PRCS without host coordination under §1910.146(j); same §1910.146 violation cited within 5 years
Serious	$16,132	Substantial probability of death or serious physical harm from an entry without a verified written program, an entry without isolation of mechanical/electrical energy (i.e. missing §1910.147 LOTO prerequisite), a rescue service not summoning within the entry-supervisor-defined rescue window, or atmospheric testing omitted or performed in the wrong order with documented entrant exposure
Other-than-Serious	$16,132	Missing written program signature under §1910.146(c)(4), missing annual program review under §1910.146(c)(7), missing post-entry review / cancellation documentation under §1910.146(d), missing or unsigned training records under §1910.146(i), or missing contractor host-coordination debrief under §1910.146(j)
Failure to Abate	$16,132/day	PRCS written-program gap, atmospheric-testing protocol not corrected, rescue-summon-window verification not corrected, or contractor-coordination debrief not corrected by the OSHA-specified abatement deadline

Note: A single permit-required confined-space entry can produce multiple §1910.146 citations — a missing written program, a missing entry permit, an atmospheric test performed in the wrong order, a non-trained attendant, an unverifiable rescue service, and a missing host-contractor coordination debrief each represent independent compliance duties under 29 CFR 1910.146.

Source: OSHA penalty adjustment schedule. Amounts are updated annually under the Federal Civil Penalties Inflation Adjustment Act Improvements Act of 2015.

Pre-Entry PRCS Walkthrough

Permit-required confined-space pre-entry checklist — five items to confirm before an entrant crosses the plane of the opening

These five items map to the in-app Permit-Required Confined Space category on the Sentinel Safety Daily Inspection template — space reclassified and entry permit posted, atmospheric testing performed with a calibrated four-gas monitor in the required order, attendant assigned with continuous communication and verified rescue summon, rescue service confirmed via a written rescue plan with a practice entry in the prior 12 months, and authorized entrants trained on the hazards of this specific space. Run them on paper on the shop floor and inside Sentinel Safety in the office so the same checklist governs every entry.

Space reclassified and the entry permit posted at the entry point before any entrant crosses the plane of the opening; LOTO isolation verified under §1910.147 for mechanical / electrical / hydraulic / pneumatic / thermal energy before entry begins
Atmospheric testing performed with a calibrated four-gas monitor in the required order — oxygen (19.5%–23.5%), flammability (<10% LEL), toxicity (<PEL) — and acceptable entry conditions verified before entry and continuously or periodically monitored per the permit
Attendant assigned at the entry point with a continuous communication method (voice / visual / radio) to each entrant; the attendant has no other duties that interfere with monitoring the entry and holds the summon capability for the rescue service
Rescue service confirmed via a written rescue plan and a permitted-space rescue practice entry in the prior 12 months; rescue service can meet the entry-supervisor-defined summon window for this specific space with one-entry-per-rescuer staffing and CPR/first-aid certified rescuers
Authorized entrants trained on the hazards of this specific space under §1910.146(i); hot-work permit (when required) issued separately; contractor coordination documented under §1910.146(j) when host and contractor share a permit space

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Common Questions

Permit-Required Confined Spaces under 29 CFR 1910.146, answered

Related OSHA Manufacturing & Construction Pages

Three pages that bind to permit-required confined space in a manufacturing program

Permit-required confined space entry never stands alone in a manufacturing program — it pairs with the §1910.147 LOTO prerequisite that must isolate every mechanical/electrical hazard before entry begins, with the §1910.134 respiratory protection program that supplies the entrant’s air and the attendant’s rescue SCBA, and with the EHS software layer that runs the entry permit cycle, the atmospheric test log, the rescue practice calendar, and the contractor coordination debrief. These three pages cover the adjacent programs a PRCS coordinator needs on the same job.

29 CFR 1910.147

Lockout/Tagout Safety

29 CFR 1910.147 hazardous-energy control is the prerequisite to any PRCS entry where mechanical, electrical, hydraulic, pneumatic, chemical, or thermal energy could harm an entrant. The LOTO program supplies the verified zero-energy state that the §1910.146(d) entry permit references as the isolation control, and the authorized LOTO employee hands the permit-ready machine off to the entry supervisor before entry begins.

Read the LOTO safety page

29 CFR 1910.134

Respiratory Protection Safety

29 CFR 1910.134 governs the entrant’s respirator selection and the rescue service’s SCBA / supplied-air equipment that meet §1910.146(h) and IDLH atmosphere entry. The PRCS permit references the §1910.134 program — medical evaluation, fit testing, training — for any entrant breathing through an air- purifying or supplied-air respirator inside the permit space.

Read the respiratory protection page

29 CFR 1910 General Industry

Manufacturing EHS Software

Sentinel Safety automates the §1910.146 written PRCS program, the PRCS space inventory and decision tree, the entry-permit cycle with posted-at-entry-point attestation, the atmospheric test log with four-gas monitor calibration reminders, the rescue practice calendar keyed to §1910.146(h) once-per-12-months, host-contractor coordination debriefs, training records, OSHA 300 / 300A / 301 record-keeping, and AI-powered incident reports.

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Stop managing §1910.146 PRCS permits, atmospheric tests, and rescue-summon windows with clipboards and spreadsheets

Sentinel Safety automates the §1910.146 written permit-required confined space program, the PRCS space inventory and decision tree, the entry permit cycle with posted-at-entry-point attestation, atmospheric test logs with four-gas monitor calibration reminders, rescue practice calendar keyed to §1910.146(h) once-per-12-months, host-contractor coordination debriefs, training records per §1910.146(i), OSHA 300 / 300A / 301 record-keeping tied to PRCS incidents, and AI-powered incident reports — so EHS managers can run the PRCS program, not the paperwork.

14-day free trial. No credit card. No per-user fees.

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