The client (or their representative) must notify the Administration of Occupational Safety and Health of the construction site before work begins, if the project involves construction or civil engineering work that is expected to last more than 30 working days and more than 20 employees will be working on site at the same time. 
The same applies to work sites where the total work effort is expected to exceed 500 person-days. This may, for example, apply to a project where five workers are expected to be employed for just over three months, or approximately 100 days. 

The Administration is authorized to impose administrative fines on the client if they fail to submit advance notification of the work site. 

• A construction site notification is done on the Occupational Safety and Health Administration's website, where further information can also be accessed.