The hazard
Confined spaces can look harmless from the outside. The air inside can be short on oxygen or hold toxic or flammable gas you may not see or smell, and loose material like sand or grain can bury a worker. When someone goes down, the natural reaction is to rush in and help, and that can turn one victim into two.
The action
Tanks, vaults, pits, manholes, silos and crawl spaces have a few things in common. You can get inside, the ways in and out are limited, and they are not built for people to stay in. On a construction site, a competent person must identify every confined space the crew may work in before work starts, and flag which ones are permit spaces. (29 CFR 1926.1203(a))
ASK THE CREW
Which spaces on this job could be confined spaces, and which ones are marked as permit spaces?
From the talk: Confined spaces. Read it in full, free, with the questions and the sign-in sheet.