Confined Space Program: What OSHA Requires and How to Build It

Your facility has spaces workers enter for maintenance, cleaning, or inspection. Some of those spaces are just tight. Others can kill a worker in minutes. The difference is what your confined space program is built to identify.

OSHA’s permit-required confined space standard, 29 CFR 1910.146, has been cited thousands of times. The violations aren’t complex. They come from facilities that either didn’t write a program, didn’t train workers, or assumed “call 911” was a rescue plan. It isn’t.

What Is a Confined Space (and When Does It Become Permit-Required)

A confined space has three features: large enough for a worker to enter and perform work, limited means for entry or exit, and not meant for continuous occupancy. Tanks, vessels, silos, storage bins, hoppers, vaults, pits, manholes, tunnels, agitators, and ducts are common examples.

Not every confined space needs a permit. A space becomes permit-required when it has or has the potential for a serious hazard. OSHA defines four trigger conditions: a hazardous atmosphere (or potential for one), material that could engulf an entrant, an internal shape that could trap or asphyxiate an entrant, or any other recognized serious safety or health hazard.

The “potential for” language matters. You can’t test the atmosphere, find it clean, and skip the permit. If your process could introduce a hazardous atmosphere, the space stays permit-required until you’ve controlled those hazards through isolation, not just measurement.

The Five Core Requirements of a Written Confined Space Program

OSHA requires a written program if you have permit-required confined spaces. The program doesn’t need to be long, but it needs to cover five things.

First, you have to identify and inventory all permit-required confined spaces on the property. OSHA requires posting danger signs at or near each one. If posting isn’t practical, you must communicate hazard information to workers through training.

Second, classify each space. Spaces with hazards that can be completely controlled through isolation and lockout may qualify for reclassification as non-permit for a specific entry. Spaces with atmospheric hazards that can be continuously controlled may enter under an alternate procedure. Everything else gets a full permit.

Third, develop entry permits for each type of space. A permit documents who is entering, who is the attendant, who is the entry supervisor, what hazards exist, what controls are in place, what atmospheric tests were taken, and what emergency procedures apply.

Fourth, designate and train authorized entrants, attendants, and entry supervisors. These are three distinct roles with different duties. Training records must be kept. Roles can’t be combined except where the standard specifically allows it.

Fifth, establish rescue provisions. This is where most programs fail.

Atmospheric Testing: What to Test and In What Order

Before any worker enters a permit-required space, the atmosphere must be tested. This applies even if the space “always tests clean.” You test for oxygen content first, flammable gases second, and toxic air contaminants third. The order matters because a flammable gas meter may not function accurately in an oxygen-depleted atmosphere.

Oxygen must be between 19.5 and 23.5 percent. Below 19.5 is oxygen-deficient. Above 23.5 is oxygen-enriched, which dramatically raises the risk of fire and explosion. Flammable gas readings must be below 10 percent of the lower explosive limit (LEL) before entry. Common toxic hazards include carbon monoxide (ceiling 200 ppm per OSHA PEL) and hydrogen sulfide (ceiling 20 ppm).

Atmospheric testing continues throughout the entry. The entrant’s own air monitoring is not a substitute for an adequately calibrated meter operated at multiple levels inside the space. Gases stratify. What’s safe at waist height can be IDLH at the floor.

Document every test: location, time, result, name of tester, calibration date of the meter. That documentation is part of the permit.

The Attendant’s Role

The attendant stays outside the space. Always.

This isn’t a suggestion. An attendant who enters the space cannot perform attendant duties from inside it. The attendant tracks who is inside, monitors conditions from outside, maintains communication with entrants, watches for signs of behavioral changes or impaired judgment, monitors for hazards outside the space that could affect the entry, and orders evacuation when anything goes wrong. The attendant also keeps unauthorized personnel out.

The attendant is not a supervisor, not a spotter, and not a backup entrant. If the attendant needs to leave, the entry stops and entrants come out first. There is no “quick entry” exception.

Communication requirements are direct: the attendant must be able to maintain contact with each entrant throughout the entry. This means voice, visual, phone, or radio. The method must be documented on the permit.

Rescue Provisions: Why “Call 911” Fails

OSHA requires rescue provisions before entry begins, not after a worker is in trouble. This is the part of confined space programs most commonly written badly.

“We will call 911” is not an acceptable rescue plan. A local fire department may take 5 to 15 minutes to arrive. Workers incapacitated by a hazardous atmosphere die in under 4 minutes in some scenarios. By the time a fire department arrives, a non-entry retrieval that could have happened in 30 seconds has become a body recovery.

You have three options. Non-entry retrieval with a retrieval system (chest harness, wristlets, and retrieval line attached before entry) allows an attendant to pull an incapacitated worker out without entering the space. This is the fastest option and should be used wherever the space configuration allows it. It won’t work in every space, particularly those with internal baffles or turns.

Rescue by a trained, equipped on-site or contracted rescue team is the second option. The team must have current training, equipment, and practice opportunities. OSHA requires you to evaluate potential rescue service capability. That means actually visiting or confirming the team can respond in time and handle the specific hazards in your spaces.

The third option is a local fire department with documented confined space rescue capability. Before listing them in your program, you need a pre-arrangement letter confirming they will respond, their response time, and their equipment for your specific type of space. You can’t list a department as your rescue provider without confirming they can actually do the job.

Real programs use retrieval systems as the first line for accessible spaces and have a trained team on call for spaces where retrieval won’t work.

Reclassifying a Permit-Required Space

Some permit-required spaces can be reclassified as non-permit for a specific entry. This applies when the only hazard is an atmospheric one, and that hazard can be completely controlled through forced-air ventilation alone, without needing any other permits or procedures.

The process: test the atmosphere before entry. Use continuous forced-air ventilation. Test again. Document the conditions. If testing confirms the space is safe and remains safe with ventilation running, the entry supervisor may authorize entry under the reclassified status without a full permit.

If the ventilation stops working during the entry, workers exit immediately. The reclassified status applies only when the control measure is actively functioning.

You cannot reclassify a space where engulfment, entrapment, or LOTO hazards exist. Those require a full permit regardless of atmospheric readings.

Construction Confined Spaces Under 1926 Subpart AA

General industry confined spaces fall under 29 CFR 1910.146. Construction sites fall under 29 CFR 1926 Subpart AA, which OSHA finalized in 2015 after decades of applying the general industry rules by reference.

The construction rule adds a controlling contractor layer. When a general contractor manages a site where subs will perform work in or near a confined space, the GC must identify and communicate hazard information to those subs before work begins. If a sub creates new hazards or reclassifies a space, they have to inform the GC and other affected contractors.

The standard also requires coordination when multiple employers are working in the same space or when the entry of one employer’s workers could affect another employer’s hazards. This is a common gap in construction safety programs where each subcontractor assumes someone else is managing the space.

Training requirements are essentially the same. The permit process mirrors 1910.146. The key difference is the contractor coordination layer, which is unique to the construction rule.

Training Requirements

Every worker who will be an authorized entrant, attendant, or entry supervisor needs training before performing those duties. Training must cover the hazards they’ll encounter, the procedures they’ll follow, and the equipment they’ll use.

Initial training happens before assignment. Refresher training is required when duties change, when there’s reason to believe a worker lacks the required knowledge, or when the space program is revised. Many safety programs set annual refreshers. That’s a practical standard, not an OSHA minimum.

Training records must include the employee’s name, the trainer’s name, and the training date. Certificates alone don’t satisfy this. You need records showing each worker’s role and the content covered.

Entry supervisors need additional training on permit verification and cancellation procedures. They must understand when to cancel an entry, not just how to start one.

Common OSHA Citations Under 1910.146

The most common serious citations are no written confined space program or hazard assessment, failure to develop entry permits, no atmospheric testing program, inadequate or absent rescue provisions, and failure to train workers in their specific roles.

OSHA also frequently cites atmospheric testing failures, specifically failure to test before entry, failure to test at multiple levels, and using meters that aren’t calibrated or maintained.

The no-rescue-provisions citation hits employers who list “call 911” as their plan without confirming fire department response capability or providing any retrieval equipment.

For deeper work on how OSHA citations are generally handled, the most cited OSHA violations guide gives broader context. If your program connects to lockout/tagout procedures for isolating hazards before entry, see the LOTO program guide.

The OSHA 30 General Industry certification includes confined space content and is a reasonable credential for entry supervisors managing complex programs.

FAQ

The Bottom Line

Write the permit. Test the atmosphere. Assign a real attendant. And actually pre-arrange your rescue.

The fatalities in confined spaces rarely come from novel hazards. They come from programs that existed on paper and collapsed at the moment of entry. The most common scenario is still a worker incapacitated inside, a coworker entering without equipment to help, and two fatalities instead of one.

Pre-arrange and test your rescue plan before you need it. That means actually attaching a retrieval harness, pulling it, and confirming the hardware works in your specific spaces. Paper rescue plans fail in real entries.