Selecting a qualified contractor is only the start. Under 29 CFR 1910.119(h)(2)(v), the host employer must periodically evaluate the performance of contract employers in fulfilling their obligations under (h)(3): training their employees in safe work practices and in the process hazards and emergency plan, documenting that training and how understanding was verified, making sure their employees follow the facility's safety rules, and reporting unique hazards they create or find. The standard doesn't set a frequency. The letters below show what OSHA expects the evaluation to look at.

What OSHA Has Said

Jan 26, 1993
Shared responsibility, and how to evaluate a contractor
In a letter about ammonia refrigeration maintenance, OSHA described responsibility for contractor safety as shared: the host creates and controls the hazards and has primary responsibility, while the contractor trains its own people. Under PSM, the host must give the contract employer process information and periodically evaluate how the contractor is meeting its training duties. For managers without PSM experience, OSHA suggested training, an outside consultant, or a designated manager, and pointed to its compliance directive.
Read OSHA Letter ↗
Feb 16, 2022
Host-provided training for contract employees
A host employer can deliver the hazard and emergency-plan training required by (h)(3)(ii) and prepare the records, but the contract employer must make sure that training and documentation are adequate, including how understanding was verified, keep the records (employee identity, training date, and means used to verify understanding), train new employees before they work, and still provide job-skills training under (h)(3)(i). The contract employer also remains responsible under (h)(3)(iv) for making sure its people follow the facility's safety rules.
Read OSHA Letter ↗
Mar 16, 2005
Controlling who enters the process area
OSHA said the safe work practices required by (f)(4) must control entry into a facility by maintenance, contractor, laboratory, and other support personnel, including supervisors and people only planning future work, so operators know who is in their area and everyone can be accounted for in an emergency. Under (h)(2)(iv), the host must also control the entrance, presence, and exit of contractors. OSHA enforces the procedure the employer writes, and recommends one consistent entry practice for all groups.
Read OSHA Letter ↗

⚡ Key Compliance Takeaway

Build contractor evaluation into the job, not just the bid. Spot-check contractor training records for identity, date, and how understanding was verified; observe whether crews follow your permits and entry controls; and keep a record of what you checked and what you did about gaps. Repeat it at a sensible interval and after any incident or near miss involving a contractor.