Testing Before Re-entry Confined Space Toolbox Talk

Confined space conditions can change after workers leave the space. Breaks, shift changes, ventilation shutdowns, rain, flooding, chemical use, nearby equipment, hot work, or material movement can change the air and create hazards that were not present during the first entry.

This talk focuses on testing before re-entry into a confined space. The goal is to make sure the crew does not assume the space is still safe just because it was tested earlier in the day.

Why This Matters

• Oxygen levels, flammable vapors, and toxic gases can change when work stops or ventilation changes.
• Rain, flooding, sewage flow, or nearby work can introduce new gases or reduce safe access.
• Solvents, coatings, welding, cutting, cleaning, or fuel-powered equipment can affect air quality after the original test.
• Re-entry without testing can expose workers to hazards that developed while the space was empty.
• Retesting confirms the permit conditions are still valid before workers go back inside.

Common Hazards

• Re-entering after lunch, break, or shift change without retesting the atmosphere.
• Assuming ventilation kept the space safe when the blower stopped, ducting moved, or power was lost.
• Entering after an alarm without identifying the cause and confirming safe readings.
• Failing to test the top, middle, bottom, and actual work area before re-entry.
• Letting new work nearby introduce exhaust, fumes, dust, vapors, or flammable gases.
• Using a gas meter that has low battery, failed bump test, expired calibration, or damaged sensors.
• Re-entering a manhole, pit, or vault after rain or water flow changes without checking for gas buildup or low oxygen.

Safety Checklist

Before Work Begins

• Review the confined space permit and confirm when re-entry testing is required.
• Confirm the gas meter is calibrated, bump tested, charged, and set up for the expected hazards.
• Plan retesting after breaks, shift changes, ventilation changes, alarms, weather changes, or changes in work activity.
• Confirm who is authorized to test the atmosphere and record readings.
• Keep the entry point controlled so no one re-enters before testing is complete.
• Make sure ventilation, communication, attendant duties, and rescue controls are still in place.

During Work

• Test the atmosphere before re-entry whenever the permit requires it or conditions may have changed.
• Check oxygen first, then flammable gases and vapors, then toxic gases as required.
• Test the top, middle, bottom, and the actual work location inside the space.
• Confirm ventilation is running and fresh air is reaching the work area before workers go back in.
• Record readings on the permit or entry log as required by the site plan.
• Do not re-enter until safe readings are confirmed and the attendant allows entry.

Crew Talking Points

• What conditions would require us to retest before going back into this space?
• Who is responsible for testing and documenting the air readings?
• Did ventilation, weather, nearby work, tools, chemicals, or material conditions change while the space was empty?
• How will we keep the entry point controlled so no one re-enters early?
• Does anyone have questions or concerns about re-entry testing, monitor readings, ventilation, alarms, or permit conditions?

Stop Work If

• Workers are about to re-enter without required atmospheric testing.
• The permit is expired, incomplete, or does not reflect current conditions.
• The gas meter is not calibrated, bump tested, charged, or working correctly.
• Readings are outside the allowed entry limits or change during testing.
• Ventilation, communication, attendant coverage, rescue access, or entry control is not in place.

Final Reminder

Safe air earlier does not mean safe air now. Retest before re-entry, confirm the permit conditions, and do not go back in until the space is proven safe.