OSHA general industry permit-required confined spaces practice questions
20 free practice questions from 29 CFR 1910.146. Each answer is explained and linked to the rule it comes from.
OSHA Permit-required confined spaces
20 questions across 8 topics. After each answer you see why it is right, with a link to the official source.
Tip: press A, B, C or D to answer and Enter for the next question. Nothing you answer leaves your browser.
Review all 20 questions
Prefer to read? Here is every question in the OSHA Permit-required confined spaces set, grouped by topic. Open a question to see the answer, why it is right and the official source.
Scope and definitions
1. Under 1910.146(a), which type of employment is outside the scope of the permit-required confined spaces section?
- A. Warehouse employment
- B. Construction
- C. Food processing employment
- D. Chemical plant employment
Show answer
Answer: B. Construction
The section "does not apply to agriculture, to construction, or to shipyard employment".
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
2. What does the note to the 1910.146(b) definition of inerting say about the atmosphere that inerting produces?
- A. It makes the space safe to enter without respiratory protection
- B. It produces an oxygen-enriched atmosphere
- C. It produces an atmosphere that needs no further testing
- D. It produces an IDLH oxygen-deficient atmosphere
Show answer
Answer: D. It produces an IDLH oxygen-deficient atmosphere
Inerting means displacing the atmosphere "by a noncombustible gas (such as nitrogen) to such an extent that the resulting atmosphere is noncombustible," and the note states "This procedure produces an IDLH oxygen-deficient atmosphere."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
3. Under the note to the 1910.146(b) definition of entry supervisor, may an entry supervisor also serve as an attendant or as an authorized entrant?
- A. Yes, as long as that person is trained and equipped as required by the section for each role he or she fills
- B. No, the roles must always be held by different people
- C. Only in permit spaces with no atmospheric hazard
- D. Only with written approval from OSHA
Show answer
Answer: A. Yes, as long as that person is trained and equipped as required by the section for each role he or she fills
The note says "An entry supervisor also may serve as an attendant or as an authorized entrant, as long as that person is trained and equipped as required by this section for each role he or she fills."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
4. How does 1910.146(b) define blanking or blinding?
- A. The absolute closure of a pipe, line, or duct by fastening a solid plate that completely covers the bore and can withstand the maximum pressure with no leakage beyond the plate
- B. Closing a single valve in the line and tagging it
- C. Covering the entrance portal of the space with a tarp
- D. Turning off the lighting inside the space
Show answer
Answer: A. The absolute closure of a pipe, line, or duct by fastening a solid plate that completely covers the bore and can withstand the maximum pressure with no leakage beyond the plate
Blanking or blinding "means the absolute closure of a pipe, line, or duct by the fastening of a solid plate (such as a spectacle blind or a skillet blind) that completely covers the bore and that is capable of withstanding the maximum pressure of the pipe, line, or duct with no leakage beyond the plate."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Hazardous atmospheres and engulfment
5. For an air contaminant for which OSHA has not determined a dose or permissible exposure limit, what does the note to the 1910.146(b) definition of hazardous atmosphere say can provide guidance in establishing acceptable atmospheric conditions?
- A. Only the entrants' own judgment of odor
- B. Nothing, because such a contaminant can never create a hazardous atmosphere
- C. Other sources of information, such as Material Safety Data Sheets that comply with the Hazard Communication Standard (1910.1200), published information, and internal documents
- D. Only a written ruling from the OSHA area office
Show answer
Answer: C. Other sources of information, such as Material Safety Data Sheets that comply with the Hazard Communication Standard (1910.1200), published information, and internal documents
The note says "For air contaminants for which OSHA has not determined a dose or permissible exposure limit, other sources of information, such as Material Safety Data Sheets that comply with the Hazard Communication Standard, § 1910.1200 of this part, published information, and internal documents can provide guidance in establishing acceptable atmospheric conditions."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
6. The note to the 1910.146(b) definition of IDLH names hydrogen fluoride gas and cadmium vapor as materials whose transient effects may be followed by sudden, possibly fatal collapse. How long after exposure?
- A. 1-2 hours
- B. 12-72 hours
- C. 1-2 weeks
- D. 30 days
Show answer
Answer: B. 12-72 hours
The note says such materials "may produce immediate transient effects that, even if severe, may pass without medical attention, but are followed by sudden, possibly fatal collapse 12-72 hours after exposure."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Workplace evaluation, warning signs and contractors
7. If the employer decides that its employees will enter permit spaces, what does 1910.146(c)(4) require?
- A. An oral program explained to each entrant, with nothing in writing
- B. A program kept confidential from employees
- C. A program filed with OSHA before the first entry
- D. A written permit space program that complies with the section and is available for inspection by employees and their authorized representatives
Show answer
Answer: D. A written permit space program that complies with the section and is available for inspection by employees and their authorized representatives
The employer "shall develop and implement a written permit space program that complies with this section. The written program shall be available for inspection by employees and their authorized representatives."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
8. What does 1910.146(c)(3) require of an employer that decides its employees will not enter permit spaces?
- A. Nothing further, because the section no longer applies to it
- B. Only a written notice to OSHA that no entries will take place
- C. Effective measures to prevent its employees from entering the permit spaces
- D. Entry permits for each permit space every day
Show answer
Answer: C. Effective measures to prevent its employees from entering the permit spaces
That employer "shall take effective measures to prevent its employees from entering the permit spaces" and must still comply with paragraphs (c)(1), (c)(2), (c)(6) and (c)(8).
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
9. When does 1910.146(c)(8)(v) require the host employer to debrief the contractor?
- A. Only if someone is injured during entry
- B. At the conclusion of the entry operations
- C. Once a year at the program review
- D. Before the contractor is hired
Show answer
Answer: B. At the conclusion of the entry operations
The host employer must "Debrief the contractor at the conclusion of the entry operations" on the program followed and any hazards confronted or created.
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Alternate procedures and reclassification
10. To use the alternate procedures in 1910.146(c)(5), the employer must be able to demonstrate that the only hazard posed by the permit space is which one?
- A. A material that could engulf an entrant
- B. An actual or potential hazardous atmosphere
- C. Inwardly converging walls
- D. Moving machinery inside the space
Show answer
Answer: B. An actual or potential hazardous atmosphere
The employer must demonstrate "that the only hazard posed by the permit space is an actual or potential hazardous atmosphere".
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
11. Under the alternate procedures in 1910.146(c)(5)(ii)(E), where must the air for the continuous forced air ventilation come from?
- A. From a clean source, and it may not increase the hazards in the space
- B. From inside the space, recirculated through the fan
- C. From a compressed oxygen cylinder
- D. From any source, as long as the fan runs continuously
Show answer
Answer: A. From a clean source, and it may not increase the hazards in the space
The rule says "The air supply for the forced air ventilation shall be from a clean source and may not increase the hazards in the space."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
12. What does the note to 1910.146(c)(7) say about controlling atmospheric hazards through forced air ventilation?
- A. It counts as elimination once it has run for one hour
- B. It counts as elimination when the entry supervisor certifies it
- C. It does not constitute elimination of the hazards
- D. It allows reclassification for the rest of the shift
Show answer
Answer: C. It does not constitute elimination of the hazards
The note states: "Control of atmospheric hazards through forced air ventilation does not constitute elimination of the hazards."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
13. Under 1910.146(c)(7)(iv), what must each employee do if hazards arise within a permit space that has been declassified to a non-permit space?
- A. Exit the space
- B. Finish the current task and then report the hazard
- C. Put on a respirator and continue working
- D. Keep working while the attendant tests the atmosphere
Show answer
Answer: A. Exit the space
If hazards arise in a declassified space, "each employee in the space shall exit the space", and the employer then reevaluates it.
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Permit space program
14. Under 1910.146(d)(4), on what cost basis must the employer provide equipment such as testing, ventilating, lighting and rescue equipment?
- A. Employees pay for half of the cost
- B. Employees pay for their own personal protective equipment only
- C. Employees pay unless the equipment is reused
- D. At no cost to employees
Show answer
Answer: D. At no cost to employees
The employer must provide the listed equipment "at no cost to employees, maintain that equipment properly, and ensure that employees use that equipment properly".
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Entry permits
15. How does 1910.146(e)(3) require the completed entry permit to be made available to authorized entrants at the time of entry?
- A. By mailing it to each entrant's home
- B. By keeping it locked in the supervisor's office
- C. By reading it aloud once at the start of each year
- D. By posting it at the entry portal or by any other equally effective means
Show answer
Answer: D. By posting it at the entry portal or by any other equally effective means
The completed permit "shall be made available at the time of entry to all authorized entrants or their authorized representatives, by posting it at the entry portal or by any other equally effective means, so that the entrants can confirm that pre-entry preparations have been completed."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
16. Under 1910.146(e)(6), what must be noted on the pertinent entry permit so that appropriate revisions to the permit space program can be made?
- A. The weather on the day of entry
- B. Each authorized entrant's home address
- C. Any problems encountered during an entry operation
- D. The cost of the entry operation
Show answer
Answer: C. Any problems encountered during an entry operation
Canceled permits are kept at least 1 year for the program review, and "Any problems encountered during an entry operation shall be noted on the pertinent permit so that appropriate revisions to the permit space program can be made."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
17. Under 1910.146(e)(5), which event requires the entry supervisor to terminate entry and cancel the entry permit?
- A. A condition that is not allowed under the entry permit arises in or near the permit space
- B. An authorized entrant takes a scheduled break
- C. A new attendant takes over at a shift change
- D. The permit is posted at the entry portal
Show answer
Answer: A. A condition that is not allowed under the entry permit arises in or near the permit space
The entry supervisor must terminate entry and cancel the permit when entry operations are completed or when "A condition that is not allowed under the entry permit arises in or near the permit space."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Training and duties of entry roles
18. What must the training certification required by 1910.146(g)(4) contain?
- A. Only the name of the training company
- B. The trainer's license number and the course price
- C. The employee's home address and date of birth
- D. Each employee's name, the signatures or initials of the trainers, and the dates of training
Show answer
Answer: D. Each employee's name, the signatures or initials of the trainers, and the dates of training
"The certification shall contain each employee's name, the signatures or initials of the trainers, and the dates of training."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
19. Under 1910.146(i)(8), what must an attendant do when unauthorized persons approach a permit space while entry is underway?
- A. Enter the space to warn the entrants in person
- B. Warn the unauthorized persons that they must stay away from the permit space
- C. Ignore them unless they enter the space
- D. Leave the post to call the local OSHA office
Show answer
Answer: B. Warn the unauthorized persons that they must stay away from the permit space
When unauthorized persons approach or enter, the attendant must "Warn the unauthorized persons that they must stay away from the permit space," advise them to exit immediately if they have entered, and inform the authorized entrants and the entry supervisor if they have entered.
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)
Rescue, emergency services and employee participation
20. Under 1910.146(k)(1)(v), what must an employer that designates a rescue team or service provide to it?
- A. A copy of each entrant's medical records
- B. Payment in advance for a full year of service
- C. Access to all permit spaces from which rescue may be necessary, so it can develop appropriate rescue plans and practice rescue operations
- D. A key to the employer's main office, with nothing else
Show answer
Answer: C. Access to all permit spaces from which rescue may be necessary, so it can develop appropriate rescue plans and practice rescue operations
The employer shall "Provide the rescue team or service selected with access to all permit spaces from which rescue may be necessary so that the rescue service can develop appropriate rescue plans and practice rescue operations."
Source: eCFR: 29 CFR 1910.146, Permit-required confined spaces (as of Nov 3, 2026)