OSHA 1910.95(d): Noise Monitoring Requirements — Plain Language Guide

This plain-language guide covers OSHA 29 CFR 1910.95 1910.95(d) — Monitoring — explaining exactly what the section requires, what it means in practice for EHS managers, and the most common compliance gaps. According to CDC/NIOSH, approximately 22 million U.S. workers are exposed to hazardous occupational noise annually. See the complete OSHA 1910.95 guide for the full standard overview.

Soundtrace delivers audiometric testing and noise monitoring that meets every 1910.95 requirement — including monitoring — supervised by a licensed audiologist.

The Trigger: When Monitoring Is Required

1910.95(d)(1): "When information indicates that any employee's exposure may equal or exceed an 8-hour time-weighted average of 85 decibels, the employer shall develop and implement a monitoring program."

The word "may" is important. Monitoring is required when there is reason to believe exposure could reach 85 dBA TWA — not after confirmed exposure. If a new process is installed that involves grinding, welding, or other noise-generating activity, monitoring is required before the employer can conclude workers are below the action level.

Instrument Requirements

1910.95(d)(2)(i): Monitoring must use instruments that comply with ANSI S1.25-1991 (for dosimeters) or ANSI S1.4-1983 (for sound level meters). All instruments must be calibrated before each use per manufacturer specifications.

1910.95(d)(2)(ii): For monitoring, all continuous, intermittent, and impulsive sound levels from 80 dBA to 130 dBA must be integrated (measured and included in dose calculations). Levels below 80 dBA are excluded from OSHA dose calculations.

When Re-Monitoring Is Required

1910.95(d)(3): "If there are significant changes in production, process, equipment, or controls that may increase noise levels to the extent that additional employees may be exposed to noise levels at or above the action level, or the attenuation provided by hearing protectors being used by employees may be rendered inadequate, the employer shall conduct additional monitoring."

Triggering events that require re-monitoring:

• New or different equipment installed in a noise-monitored area
• Process changes that alter the type, duration, or frequency of noise-generating operations
• Staffing changes that move workers into previously-unmonitored noise zones
• Building or layout changes that alter noise propagation
• Equipment aging that increases noise levels (worn bearings, resonant structures)

Employee Participation Rights

1910.95(d)(4): "The employer shall allow affected employees or their representatives to observe any noise monitoring required by this section."

This is an often-overlooked requirement. Workers have the right to watch the noise monitoring process. The employer is not required to provide advance notice of the observation right, but cannot deny access when a worker or representative requests to observe.

Documentation Requirements

1910.95(m)(3): Noise exposure measurement records must be retained for 2 years. Records must include: monitoring date, area or individual monitored, instrument identification, calibration data, and exposure results. Best practice is retaining noise monitoring records indefinitely as baseline documentation for both OSHA compliance and WC defense. A 2-year-old survey may not reflect current conditions.