OSHA vs. MSHA STS Flagging: Key Differences Explained

OSHA and MSHA both require audiometric testing and Standard Threshold Shift determination for noise-exposed workers — but their STS follow-up timelines, reportable hearing loss thresholds, age correction approaches, and recordkeeping requirements differ significantly. Facilities subject to MSHA jurisdiction, or operating in both regulatory environments, need to understand exactly where the standards diverge.

Soundtrace supports hearing conservation programs in both general industry and mining environments, with configurable STS flagging that applies the correct standard for each facility type.

Jurisdiction: When OSHA vs. MSHA Applies

OSHA 29 CFR 1910.95 applies to general industry. MSHA 30 CFR Part 62 applies to metal and nonmetal mines and surface mining operations. Facilities that include both mining and non-mining areas may have both standards applying to different areas simultaneously.

STS Criteria Compared

MSHA Reportable Hearing Loss

MSHA STS (30 CFR 62.170): 10 dB average shift — triggers notification and HPD evaluation. MSHA Reportable Hearing Loss (30 CFR 62.175): 25 dB average shift — triggers MSHA Form 7000-1 reporting. These are two separate triggers with different obligations. The 25 dB figure in MSHA’s standard is the Reportable Hearing Loss threshold, not the STS threshold.

Age Correction Differences

OSHA applies age correction only to the current audiogram before comparison. MSHA applies age correction to both the reference and annual audiogram using Tables 62-3 and 62-4, simultaneously correcting both to the same reference age. The practical effect differs by worker age and frequency.

Follow-Up Requirements Compared

Baseline Audiogram Timing

Both OSHA and MSHA require baseline audiometric testing within 6 months (12 months with mobile van) and both require the 14-hour pre-test quiet period. OSHA calls it a “baseline audiogram”; MSHA calls it a “reference audiogram.”

Recordkeeping Differences

Audiometric test records must be retained for the duration of employment under both standards. OSHA recordable events go on the OSHA 300 Log (5-year retention). MSHA Reportable Hearing Loss events go on MSHA Form 7000-1 per MSHA reporting requirements. Mining operators must maintain MSHA-specific records separately from OSHA records.

Managing Dual-Jurisdiction Programs

For dual-jurisdiction operations: maintain separate enrollment lists by regulatory jurisdiction; configure audiometric software to apply the correct STS algorithm per worker; use MSHA’s 10-day notification window for all workers; track both the 10 dB STS and 25 dB Reportable Hearing Loss thresholds separately for MSHA workers.

Frequently asked questions