Other ways to control atmospheric risk in excavations include checking atmospheric conditions before starting, using gas monitors with workers wearing personal monitors close to their breathing zone, providing natural or mechanical ventilation, working in pairs with one person at the surface as a safety observer watching conditions, making sure people know the rescue procedures, and using PPE. The Code of Practice: Confined spaces gives further guidance where an excavation is a confined space.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.