OSHA
OSHA 1910.146 — Permit-Required Confined Spaces
OSHA's rule for permit-required confined spaces. Open it before anyone goes inside a tank.
OSHA's rule for permit-required confined spaces in general industry.
Open it before anyone goes inside a tank, and when you're setting up or reviewing your shop's entry program.
Whether a given entry is permit-required is decided by the rule and your own program, not by this page. Read the current text on OSHA's site.