HOW DO YOU KNOW...
  
 .... when you're supposed to wear splash goggles?
    
 .... when you're not supposed to wear shorts?
   
 .... when it's OK (if it ever is) to wear sandals? 
    

1.

A "Hazard Assessment" must be conducted 
(responsibility of supervisor)
a. Every hazard of every task is evaluated, and PPE is prescribed for the task if appropriate.
b. This is written up as a Hazard Assessment Certification
c. Can include other safety equipment but the focus, legal requirement, is the PPE requirements.
2. The Hazard Assessment Certification is posted visibly, 

and it becomes.....

THE RULES.
3.
The rules are enforced.  
(responsibility of supervisor)