This document is about a new notation for ‘immediately dangerous to life or health’ (IDLH) in the workplace exposure standards (WES).  

An IDLH notation will indicate an airborne chemical concentration that can either: 

• cause death  

• cause immediate or delayed permanent adverse health effects to a worker 

• impede a worker’s escape from such an environment. 

You can find more information in: 

• Recommending health-based workplace exposure standards and notations  

• Workplace exposure standards review methodology