Who Is Responsible for Vendor Employee Hearing Conservation? OSHA’s Rules Explained

Across manufacturing, logistics, energy, aviation, and industrial services, more vendors are embedding full time employees inside customer facilities. These workers often perform the same tasks, use the same equipment, and face the same noise hazards as the host employer’s workforce. Yet when OSHA’s Hearing Conservation Program (HCP) applies, the responsibility is not always obvious.

The short answer is simple:

• The vendor is responsible for providing the full Hearing Conservation Program.
• The host employer is responsible for the noise environment that creates the exposure.

This structure comes from OSHA’s multi employer worksite policy and it shapes how citations are issued during inspections.

OSHA’s Split Responsibility Model

OSHA considers situations involving multiple employers under its Multi Employer Citation Policy (CPL 02 00 124). Although widely used in construction, OSHA makes clear that this policy applies to general industry as well.

In any environment where employees of different employers are working side by side, OSHA places responsibility into two categories.

1. The Employing Employer (the Vendor)

This is the company listed on the worker’s W 2.

The vendor is responsible for maintaining the complete Hearing Conservation Program required by 29 CFR 1910.95. This includes:

• Noise exposure monitoring
• Enrollment of employees exposed at or above 85 dBA TWA
• Baseline and annual audiometric testing
• Employee training at least annually
• Providing appropriate hearing protection
• Standard Threshold Shift follow up
• Recordkeeping and documentation

OSHA recommends, but does not require, earplug fit testing. The agency highlights this in the OSHA Technical Manual Section III Chapter 5, explaining that fit testing can verify the actual attenuation workers receive. Many employers use fit testing because it reduces the likelihood of STS cases.

OSHA is explicit about the vendor’s obligation:

“Each employer is responsible for their own employees, regardless of whose workplace they are in.”

Relevant external sources

• OSHA 29 CFR 1910.95 Occupational Noise Exposure
• OSHA Technical Manual Section III Chapter 5
• OSHA CPL 02 00 124 Multi Employer Citation Policy
• NIOSH Criteria for a Recommended Standard Occupational Noise Exposure

2. The Host Employer (the Customer)

The host employer controls the facility and the physical environment where the vendor’s employees work.

Responsibilities include:

• Maintaining noise levels as low as feasible
• Allowing access for vendor noise measurements
• Communicating known or newly identified noise hazards
• Maintaining machinery and equipment that may contribute to hazardous noise levels
• Alerting vendors when noise conditions change

If hazardous noise exists in the facility and the host employer does not communicate or control those conditions, OSHA can issue citations.

3. OSHA Investigations After Hearing Injuries or STS Cases

When a Standard Threshold Shift occurs or a hearing related injury is recorded, OSHA may issue citations to one or both employers.

The Vendor may be cited for failure to:

• Enroll affected employees in the HCP
• Conduct required audiograms
• Provide hearing protection
• Train employees
• Follow up on STS cases
• Maintain accurate records

The Host Employer may be cited for failure to:

• Control or maintain noise levels
• Communicate hazardous noise areas
• Provide monitoring access
• Notify vendors about noise changes
• Correct noise sources that elevate exposure

Shared citations are common when both employers contributed to the conditions.

The Clear Rule of Responsibility

If you need the simplest possible explanation:

• Vendors are responsible for the Hearing Conservation Program.
• Customers are responsible for the noise environment.
• Both employers may be cited.

Expanded Practical Example

A maintenance services vendor provides 20 technicians who work full time inside a large manufacturing plant. The plant operates stamping presses, conveyors, and grinders that often produce noise levels between 88 and 96 dBA. The vendor’s technicians work throughout the facility, often side by side with the host employer’s permanent employees.

Vendor Responsibilities in This Scenario

The vendor must:

• Conduct noise exposure monitoring for its employees or obtain reliable data from the host employer
• Enroll all technicians exposed at or above 85 dBA TWA in the HCP
• Perform baseline audiograms before or soon after assignment, followed by annual audiograms
• Provide hearing protection and ensure employees know how to insert earplugs correctly
• Provide training on hearing risks and proper use of hearing protection
• Recommend but not require earplug fit testing
• Document all results, maintain OSHA aligned records, and manage STS follow up

If OSHA found that the vendor failed to provide audiograms or did not enroll employees despite known exposures, the vendor would be cited.

Host Employer Responsibilities in This Scenario

The host employer must:

• Communicate that the production floor operates between 88 and 96 dBA
• Allow the vendor to perform noise monitoring activities
• Maintain stamping machines and grinders to avoid preventable noise increases
• Display signage in high noise areas
• Notify the vendor when production changes or machine repairs alter noise exposure
• If OSHA found that the host ignored elevated noise levels or failed to warn the vendor about unusually loud areas, the host could be cited.

Likely OSHA Outcome

If an OSHA inspection followed an STS in this example, both employers could face citations. The vendor may be cited for gaps in its HCP and the host employer may be cited for creating or failing to control the noise hazard.

This example illustrates how multi employer responsibilities function in real facilities.

Where Soundtrace Fits In

Soundtrace helps both vendors and host employers maintain compliance by offering:

For Vendors

A complete, OSHA aligned Hearing Conservation Program that includes:

• Fast baseline and annual audiograms using portable equipment
• Connected noise monitoring and exposure tracking
• Automatic STS detection and follow up workflows
• Optional earplug fit testing workflows that align with OSHA guidance
• Cloud based documentation across all customer sites

For Host Employers

Improved visibility and shared accountability through:

• Real time exposure insights for embedded vendor teams
• Shared reporting that demonstrates effective hazard communication
• Documentation support during audits
• Centralized recordkeeping that validates multi employer compliance

Vendors gain a turnkey HCP. Hosts strengthen their safety posture and reduce risk.

Frequently Asked Questions
1. Are host employers required to provide audiograms for vendor employees?

No. OSHA assigns responsibility for audiometric testing to the vendor because the vendor is the employing employer.

2. Does OSHA require earplug fit testing?

No. Fit testing is recommended by OSHA and NIOSH as a best practice but remains optional. Employers use it to ensure proper attenuation and to reduce STS cases.

3. If the host employer provides hearing protection to vendors, does this shift responsibility?

No. Even if the host employer offers PPE, the vendor still owns the HCP and must ensure its employees receive training and proper protection.

4. What happens if the vendor refuses to conduct noise monitoring?

OSHA may cite the vendor for failing to assess noise exposure. The host employer may also be cited if it prevented access or failed to communicate known hazards.

5. Is the host employer responsible for labeling high noise areas?

Yes. The host employer must identify and communicate hazard areas, especially where exposures exceed 90 dBA or where hearing protection is required.

6. Can both employers be cited for the same STS incident?

Yes. Shared liability is common. OSHA often issues citations to both employers when both contributed to unsafe conditions.

7. Does the vendor need to re enroll employees if they move to a quieter area?

Yes. The vendor must monitor exposure during workplace changes and adjust enrollment accordingly.

8. Are staffing agency employees treated the same as vendor employees?

Yes. The staffing agency is the employing employer and must provide the full HCP.

9. Can vendors rely on host employer dosimetry data?

Yes, but only if the data is reliable, current, and representative of vendor work activities.

10. What documentation should vendors provide to customers to satisfy concerns?

Typical documentation includes: HCP status reports, audiogram completion logs, STS follow up records, training completion, and proof of hearing protection provision.