Safety is Job One
Construction a dangerous profession which prescribed safety plans attempt to mitigate. However, the actual or perceived delegation of safety obligations done incorrectly can create liability. It is especially important to clarify who is to manage and monitor safety issues on any project.
Shifting The ResponsibilityWhile such a delegation may not eliminate liability if an accident were to occur, it may limit one's exposure by shifting some portion of the responsibility.
Here's what a general contractor is likely to add in any subcontract to protect itself "Subcontractor has the sole responsibility for maintaining the safety and loss prevention programs covering all Work performed by subcontractor and its subcontractors and suppliers of any and all tiers. Contractor's failure to stop subcontractor's unsafe practices shall not relieve subcontractor of its responsibility therefore."
How Subs Can Protect ThemselvesWhile subcontractors will not generally be able to escape fault for any of their unsafe job conditions, they can at least require contractors "to provide customary protective services for the Work" and "to hold its workers harmless from the presence of hazardous waste or materials at the jobsite not created, generated, delivered or stored by subcontractor."