Free lesson · 2 min read · Updated 2026-10-25
Confined Spaces at Hazardous Waste Sites: Permits, Roles and Rescue
Tanks, vaults, pits, sumps, sewers and trenches are common at cleanup sites, and the HAZWOPER site safety and health plan must include confined space entry procedures. The detailed rules come from OSHA's confined space standards: 29 CFR 1910.146 for general industry and 29 CFR 1926 Subpart AA for construction.
What counts as a confined space
A space is a confined space if it is large enough for a worker to enter, has limited or restricted ways in or out, and isn't designed for continuous occupancy. It becomes a permit-required confined space if it also has one or more of these:
- A hazardous atmosphere, or the potential for one
- Material that could engulf an entrant
- Inwardly converging walls or a floor that slopes to a smaller cross-section that could trap or asphyxiate someone
- Any other recognized serious safety or health hazard
Testing the atmosphere
Test before entry and keep monitoring while people are inside. Test in this order:
- Oxygen: acceptable range 19.5% to 23.5%
- Combustible gases and vapors: a hazardous atmosphere includes flammable gas above 10% of the lower flammable limit
- Toxic gases and vapors: compare with exposure limits
Test at different levels: top, middle and bottom. Heavy gases settle and light gases rise. Ventilation helps, but it doesn't replace testing.
The entry permit
The written permit is signed by the entry supervisor before entry and posted at the entrance. It lists the space, purpose, date and duration, authorized entrants, attendants, entry supervisor, hazards, isolation and control measures, acceptable entry conditions, test results, rescue services, communication methods and required equipment.
The three roles
| Role | Responsibilities |
|---|---|
| Authorized entrant | Knows the hazards, uses equipment correctly, stays in contact with the attendant, alerts the attendant to warning signs, and leaves when ordered or when an alarm sounds |
| Attendant | Stays outside the space for the whole entry, keeps count of entrants, monitors conditions, orders evacuation, summons rescue, keeps unauthorized people out, and never enters to attempt rescue unless relieved and trained |
| Entry supervisor | Checks the permit and conditions, authorizes entry, confirms rescue is available, and ends the entry and cancels the permit when work is done or conditions change |
Rescue
Would-be rescuers make up a large share of confined space deaths: a coworker sees someone collapse and goes in after them without protection. The plan must name a rescue service that can respond in time, and non-entry rescue with a retrieval system (harness and lifeline attached to a mechanical device for vertical spaces deeper than 5 feet) should be the default where it doesn't add risk.
Confined spaces and HAZWOPER
On a hazardous waste site, a confined space can hold unknown chemicals, so atmospheric testing ties directly into air monitoring and PPE selection. Entry in Level A or B ensembles adds heat stress and mobility problems that the plan must address. Quiz yourself with the field safety quiz.
Frequently asked questions
What makes a confined space permit-required?
Having a hazardous atmosphere or the potential for one, engulfment hazards, inwardly converging walls or a sloping floor that could trap someone, or any other serious safety or health hazard.
In what order should confined space air be tested?
Oxygen first, then combustible gases and vapors, then toxic gases and vapors.
Can the attendant enter the space to rescue an entrant?
No. The attendant stays outside and summons rescue. They may only enter if relieved by another attendant and trained and equipped for rescue.
This guide summarizes federal OSHA, Cal/OSHA and EPA rules for training purposes. It is not legal advice. Always check the current regulation text and your site safety and health plan.