Silent Hazards: The Critical Steps Before Entering a Confined Space

A confined space can look completely harmless. A manhole, a tank, a pit or a vessel might be dry, quiet and empty, and still contain air that will kill you in a few breaths. Hydrogen sulfide, carbon monoxide and a lack of oxygen are invisible, and some gases dull your sense of smell before you realise anything is wrong.

The rule is: don't enter a confined space unless the atmosphere has been tested, a permit is in place, and someone outside is ready to raise the alarm and start a rescue.

What that looks like on the job

• Test before you enter, and keep testing. Use a calibrated gas detector, test at different levels, and monitor continuously while people are inside.
• Ventilate. Fresh air going in is one of the simplest and most effective controls.
• Work under a permit that names who is going in, the hazards, the controls and the rescue plan.
• Station a trained attendant outside whose duties let them continuously monitor the people inside and summon help immediately.
• Plan the rescue before the entry. Where the space and the task allow, use non-entry retrieval such as a harness and retrieval line; otherwise make sure a trained rescue team and suitable equipment are immediately available.

Real-World Impact

In January 2017, on a road project in Key Largo, Florida, a pipe layer climbed down into a manhole and quickly collapsed. A co-worker went in to help him and also collapsed. A third man followed them both. All three died. Testing afterwards found lethal levels of hydrogen sulfide and carbon monoxide, and a volunteer firefighter was also overcome during the rescue but survived. OSHA cited the employers for failing to ventilate the space, test the atmosphere, use an entry permit, train the workers, or provide rescue equipment.

Source: U.S. Occupational Safety and Health Administration (OSHA), July 2017

The Key Largo tragedy follows a pattern safety researchers have warned about for decades: when someone collapses in a confined space, the instinct to jump in after them is overwhelming, and would-be rescuers often become victims too. NIOSH has reported that more than 60% of confined space deaths are people attempting a rescue.

Reflective Questions

• If a colleague collapsed inside a tank right now, what would you do in the first 30 seconds?
• Is our gas detector calibrated, bump-tested and actually used before every entry?
• Which spaces on our site don't look like confined spaces, but are?