34ea531b_HA__1926_Subpart_AA__1926_1200__General_Industry
[Difference] Permit-Required Confined Spaces–Early Warning Requirements [Construction] Early-warning requirement for up-stream hazards in sewer-type spaces. [General Industry] 
No specific early-warning requirements for up-stream hazards.
New Confined Spaces in Construction Standard from OSHA: 1926 Subpart AA, 1926.1200
General Industry