How to Handle Baseline Audiograms for Rehired Employees

When it comes to occupational hearing conservation, one often-overlooked challenge is managing audiometric testing for employees who return to the company after a gap in employment. Specifically, if a worker was previously terminated and then rehired two or three years later, how should their baseline audiogram be handled?

This question isn't just about medical records—it's about compliance with OSHA’s Hearing Conservation Standard (29 CFR 1910.95) and protecting your workforce from long-term hearing loss. Let’s break down the best practices and regulatory guidance on this issue.

Understanding OSHA’s Requirement

OSHA requires that a baseline audiogram be established for employees exposed to noise levels at or above 85 dBA averaged over an 8-hour TWA (Time-Weighted Average). This baseline is used as the reference point for comparing future annual audiograms to determine if a Standard Threshold Shift (STS) has occurred.

Per OSHA’s regulation, a baseline audiogram must be completed within the first 6 months of noise exposure, or within 12 months if mobile testing is used—provided that interim hearing protection is worn.

But what if the employee had a valid baseline audiogram before they left the company?

Rehires and the "New" Baseline Question

OSHA's standard does not explicitly address how to handle baseline audiograms for rehires. However, OSHA interpretations and best practices from audiologists suggest a few important principles:

1. Review the Prior Baseline
   If the previous baseline audiogram is still available in the employee’s records, it may still be valid—even after a break in service. The critical factor is whether the employee had significant occupational or non-occupational noise exposure during the gap. If they did not, the prior baseline may still accurately reflect their hearing status.

2. Consider Non-Occupational Exposure
   If the employee worked in another high-noise environment or engaged in activities such as shooting, motorcycle riding, or loud music during their time away, their hearing may have changed. In this case, it’s best to obtain a new baseline.

3. Repeat the Baseline Process If in Doubt
   Many employers choose to treat rehires as new employees for hearing conservation purposes, especially if the previous audiogram is more than a year or two old. A new baseline ensures accurate tracking and reduces risk.

4. Retain and Compare Previous Audiograms
   Even if you establish a new baseline, it’s smart to retain and review previous audiograms. This can provide valuable insight into long-term hearing trends and ensure any significant shifts are documented.

Final Recommendations

• If the prior baseline audiogram is <2 years old and no significant noise exposure occurred during the gap, consider continuing with the original baseline.

• If >2 years have passed or exposure history is uncertain, perform a new baseline audiogram within 6 months of rehire.

• Document all decisions and rationale in the employee’s file to demonstrate due diligence.

Conclusion

Rehiring former employees presents a unique opportunity to re-evaluate their hearing health and ensure compliance with OSHA standards. When in doubt, err on the side of caution: a fresh audiogram today may prevent a costly workers' comp claim tomorrow.