What is the role of the attendant?

The attendant stays outside the space for the entire entry, maintains communication with entrants, monitors conditions, orders evacuation if anything changes, and summons rescue. The attendant never enters to rescue — they initiate non-entry retrieval or call trained rescuers.

Does ventilation eliminate the need to test?

No. Ventilation reduces hazards, but you must still test before entry and monitor continuously during the entry to confirm the atmosphere stays safe. Ventilation can fail, conditions can change, and work itself can generate new contaminants.

What is a permit-required confined space?

It is a confined space that also has a hazardous or potentially hazardous atmosphere, an engulfment risk, a configuration that could trap or asphyxiate, or any other serious hazard. These spaces require a written permit, testing, an attendant, and rescue arrangements before entry.

How accurate is OSHA Scan at detecting confined-space hazards?

OSHA Scan detects unsafe confined-space entry conditions — entries without visible monitors, ventilation, attendants, or retrieval gear. It flags the entry and cites 29 CFR 1926.1204 so you can add safeguards before anyone enters.

OSHA Scan

The Air Inside a Confined Space Can Kill in One Breath

Catch untested atmospheres before anyone climbs in

Tanks, vaults, manholes, silos, and vessels can hold air that is oxygen-deficient, toxic, or flammable — invisible and instantly deadly. Most confined-space fatalities are workers and would-be rescuers overcome by the atmosphere. OSHA Scan analyzes job-site photos to flag confined-space entries without atmospheric testing, ventilation, or an attendant before anyone breathes air that could stop their heart.

An atmospheric confined-space hazard exists in any space large enough to enter but not designed for continuous occupancy, with limited entry and exit, where the air can become dangerous. The atmosphere can be oxygen-deficient (displaced by other gases or consumed by rust and decomposition), oxygen-enriched (a fire risk), toxic (hydrogen sulfide, carbon monoxide, solvent vapors), or flammable.
On job sites it shows up as a worker climbing into a manhole, sewer, storage tank, boiler, or utility vault without a gas monitor lowered first, an entry with no forced-air blower ventilating the space, or a lone worker descending with no attendant topside and no rescue plan. Rusting steel tanks quietly consume oxygen; sewers generate hydrogen sulfide and methane; recently coated vessels hold solvent vapors.
The danger is that a confined-space atmosphere gives no warning at the opening — the space looks calm and empty. A worker can lose consciousness within a breath or two of oxygen-deficient or toxic air, and coworkers who rush in to help become the next victims. That instant, multi-victim lethality is exactly why testing and photo-based detection of unsafe entries matter.

What makes a confined-space atmosphere hazardous?

The air can be oxygen-deficient (below 19.5%), oxygen-enriched (above 23.5% and a fire risk), toxic (hydrogen sulfide, carbon monoxide, vapors above limits), or flammable. Rust, decomposition, prior contents, and adjacent processes can all create these conditions invisibly.

Do I always need to test the air before entering?

Yes, for permit-required confined spaces. Test for oxygen first, then flammable gases, then toxics, and test at the top, middle, and bottom because hazardous gases stratify. Never rely on how the space looks or smells — many deadly atmospheres give no warning.

What oxygen level is safe for confined-space entry?

OSHA requires oxygen between 19.5% and 23.5% for safe entry. Below 19.5% the atmosphere is oxygen-deficient and can cause rapid collapse; above 23.5% it is oxygen-enriched and increases fire and explosion risk.

Why are so many confined-space deaths rescuers?

When an entrant collapses, coworkers instinctively climb in to help and are overcome by the same atmosphere. More than half of confined-space fatalities are would-be rescuers. This is why a trained attendant, non-entry retrieval, and a rescue plan are mandatory before entry.