Permit-Required Confined Spaces is the OSHA general industry standard that protects workers who enter tanks, silos, vaults, pits, manholes, vessels and similar spaces that can trap, asphyxiate, engulf or poison them. It requires employers to identify these spaces, keep unauthorized workers out, and control every entry through a written program and an entry permit.
Confined space incidents can claim more than one victim when a would-be rescuer enters without protection and is overcome by the same hazard. Any general industry employer with permit spaces on site must evaluate them, post warnings, and either prevent entry or run a full permit space program.
What Is the Permit-Required Confined Spaces Standard?
The rule is codified at 29 CFR 1910.146, in Subpart J of OSHA's general industry standards. It builds on two definitions in 1910.146(b).
A confined space is a space that meets all three conditions:
- It is large enough and configured so an employee can bodily enter and perform work.
- It has limited or restricted means for entry or exit.
- It is not designed for continuous employee occupancy.
A permit-required confined space is a confined space with one or more of these characteristics:
- It contains or could contain a hazardous atmosphere.
- It contains a material that could engulf an entrant.
- It has an internal shape, such as inwardly converging walls or a floor sloping to a smaller cross-section, that could trap or asphyxiate an entrant.
- It contains any other recognized serious safety or health hazard.
A hazardous atmosphere includes flammable gas, vapor or mist above 10% of its lower flammable limit, combustible dust at or above its lower flammable limit, oxygen below 19.5% or above 23.5%, and airborne concentrations above a permissible exposure limit. Entry occurs as soon as any part of the body passes through an opening into the space. For background on the broader term, see the glossary entry on confined space.
Who Must Comply?
The standard covers general industry employers. Under 1910.146(a), it does not apply to agriculture, construction or shipyard employment. Construction work in confined spaces falls under 29 CFR 1926 Subpart AA, which follows a similar permit approach but adds coordination duties among the controlling contractor, host employer and entry employers. Shipyards are covered by Part 1915.
Every covered employer must evaluate its workplace to determine whether any spaces are permit spaces, even if it never plans to send employees into them. In states with an OSHA-approved State Plan, the state's rule applies and may be stricter.
Key Requirements
Evaluation and warning, 1910.146(c)(1)–(c)(3)
Employers must identify permit spaces and inform exposed employees of their existence, location and danger, typically with signs reading "DANGER, PERMIT-REQUIRED CONFINED SPACE, DO NOT ENTER" or an equally effective method. If employees will not enter, the employer must take effective measures to prevent entry.
Written permit space program, 1910.146(c)(4) and (d)
If employees will enter, the employer needs a written program available to employees. Paragraph (d) lists what it must do, including:
- Prevent unauthorized entry and identify and evaluate hazards before entry.
- Develop procedures for safe entry, including isolation, purging, inerting, flushing or ventilating, and barriers to protect entrants from outside hazards.
- Provide testing, monitoring, ventilation, communication, lighting, PPE, entry and rescue equipment at no cost to employees.
- Test conditions before entry and during entry, in this order: oxygen, then combustible gases and vapors, then toxic gases and vapors.
- Station at least one attendant outside the space for the duration of entry.
- Designate entrants, attendants and entry supervisors, and set procedures for summoning rescue and preventing unauthorized rescuers.
- Coordinate entry when more than one employer works in a space.
Alternate procedures and reclassification, 1910.146(c)(5) and (c)(7)
Where the only hazard is an actual or potential hazardous atmosphere that continuous forced air ventilation alone can control, and monitoring and inspection data support that, the employer may use alternate procedures with a written certification instead of a full permit. A space may be reclassified as non-permit only when all hazards are eliminated, not merely controlled. Ventilation alone does not count as eliminating a hazard, and the reclassification must be certified in writing.
Entry permits, 1910.146(e) and (f)
Before entry, the entry supervisor signs a permit that documents the space, purpose, date and authorized duration, the entrants, attendants and supervisor, the hazards, isolation and control measures, acceptable entry conditions, test results with tester initials and times, rescue services and how to summon them, communication methods, required equipment, and any additional permits such as a hot work permit. The permit must be posted at the entry portal or otherwise made available, and may not last longer than the task requires.
Duties of entrants, attendants and entry supervisors, 1910.146(h)–(j)
Entrants must know the hazards, use the equipment properly, stay in contact with the attendant and exit when ordered or when they detect a warning sign. Attendants stay outside, keep an accurate count of entrants, monitor conditions, order evacuation when needed, summon rescue, and must not take on duties that interfere with monitoring. Entry supervisors verify the permit and conditions, confirm rescue services are available, and terminate the entry when needed.
Host employers and contractors, 1910.146(c)(8)–(c)(9)
A host employer that hires a contractor to enter permit spaces must tell the contractor about the spaces and their hazards, share any precautions it has used, coordinate entry, and debrief the contractor afterward. The contractor must obtain that information and report back any hazards it encountered or created.
Training, Rescue and Records
- Training, 1910.146(g): Required before an employee is first assigned duties, before a change in duties, when a new hazard arises that the employee has not been trained on, and when the employer has reason to believe the employee is deviating from procedures. Training must make the employee proficient in their duties.
- Training certification: Must include each employee's name, the signatures or initials of the trainers and the dates of training, and be available for inspection.
- Rescue, 1910.146(k): The employer must evaluate whether a rescue service can respond in a timely way for the hazards involved and is proficient. In-house rescue team members must be trained as authorized entrants, practice simulated permit space rescues at least once every 12 months, and include at least one member with current first aid and CPR certification.
- Retrieval systems: Required unless they would increase overall risk or would not contribute to rescue. A mechanical retrieval device is required for vertical spaces more than 5 feet deep.
- Cancelled permits: Must be retained for at least one year and used in the program review.
- Program review, 1910.146(d)(14): The program must be reviewed within one year after each entry, using the cancelled permits. A single annual review can cover all entries in a 12-month period.
Common Violations and Penalties
- Never evaluating the workplace to identify permit spaces.
- No warning signs or other means to keep employees out.
- Entry without a written program, a signed permit or atmospheric testing.
- Relying on the local fire department for rescue without confirming it can respond in time and has the right equipment.
- Attendants leaving their post or entering to attempt a rescue.
- Reclassifying a space as non-permit while hazards are only controlled by ventilation.
OSHA's penalties page lists a maximum of $16,550 per serious or other-than-serious violation and $165,514 per willful or repeated violation for penalties assessed after January 15, 2026. State Plan states set their own amounts.
How to Comply: Step by Step
- Survey the site. Inventory every space that meets the confined space definition and decide which are permit spaces.
- Post warnings and control access. Sign each permit space and lock or barricade those no one should enter.
- Decide who enters. Choose whether your employees, contractors or both will perform entry.
- Write the program. Cover hazard evaluation, isolation, ventilation, testing, roles, rescue, permits and contractor coordination.
- Equip the team. Provide calibrated gas monitors, ventilation, retrieval systems, communication and PPE.
- Train and certify. Train entrants, attendants, supervisors and rescuers for their specific roles.
- Arrange and evaluate rescue. Confirm response time and capability, and run practice rescues at least every 12 months.
- Issue, cancel and review permits. Keep cancelled permits for at least a year, note any problems on them, and review the program annually.
How SMS360 Helps
The SMS360 Work Permits module brings the entry permit into a digital workflow. Supervisors can complete permits with required fields such as hazards, controls, test readings and rescue arrangements, and teams can view the active permit on a mobile device at the entry point. Cancelled permits are kept in one place, which supports the annual program review. The approach mirrors a broader permit to work system.
Training records and expiry reminders help keep entrants, attendants, supervisors and rescuers current, and issues found during entries can be logged as corrective actions and tracked to closure. Related work that requires a hot work permit can be managed the same way.
Frequently Asked Questions
What is the difference between a confined space and a permit-required confined space?
A confined space is large enough to enter, has limited entry or exit and is not designed for continuous occupancy. It becomes a permit-required confined space when it also has, or could have, a hazardous atmosphere, an engulfment hazard, a trapping configuration or another serious hazard. Only permit spaces require the full permit program.
How long must confined space entry permits be kept?
Under 1910.146(e)(6), cancelled entry permits must be retained for at least one year. They are used for the annual review of the permit space program, and any problems encountered during the entry should be noted on the permit.
Can the fire department serve as the confined space rescue team?
Yes, if the employer evaluates it first. OSHA requires the employer to confirm the rescue service can respond in a timely way for the hazards involved, is proficient, and has access to the spaces for planning and practice. Simply calling 911 without that evaluation does not meet the standard.
Does the general industry standard apply to construction sites?
No. Construction work in confined spaces is covered by 29 CFR 1926 Subpart AA, which took effect August 3, 2015. It is similar to 1910.146 but adds requirements such as controlling contractor coordination, continuous atmospheric monitoring where possible and continuous monitoring of engulfment hazards.
