Personal protective equipment is designed to protect the wearer against risks to their health and/or safety.

Hazards exist in every workplace so strategies to protect workers are essential. When possible, the priority should be the elimination and control of hazards at their source or along the path between the source and the worker.

A risk assessment shall be performed by the Employer, to identify the risks and hazards in the workplace. Risk should primarily be eliminated. Personal protective equipment (PPE) should be considered as the last level of protection when all other methods to prevent risks and hazards are not available or possible. PPE is only one element in a complete safety program that would use a variety of strategies to maintain a safe and healthy workplace, and does not reduce the hazard itself nor does it guarantee permanent or total protection.

Employers are responsible for making sure that PPE requirements are being followed in the workplace.
https://www.osha.gov/laws-regs/regulations/standardnumber/1910/1910.132