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In workplace safety, a near miss is an event that could have resulted in injury or illness but didn't — due to luck, a last-second correction, or an intervention that caught the problem before it became a harm. Near misses are valuable precisely because they signal a gap in the system while there's still time to close it.
Noise-induced hearing loss has its own version of the near miss. It's called a Standard Threshold Shift.
Under OSHA 29 CFR 1910.95, a Standard Threshold Shift (STS) is defined as a change in hearing threshold relative to the baseline audiogram of an average of 10 decibels (dB) or more at 2,000, 3,000, and 4,000 Hz in either ear. When an annual audiogram reveals an STS, OSHA requires the employer to notify the worker in writing within 21 days and take a set of specific follow-up actions.
From a safety management perspective, an STS is precisely what a near miss is in other safety contexts: a measurable signal that the system of controls — noise monitoring, engineering controls, hearing protection, training — has not been sufficient to prevent early damage. The hearing loss may not yet be severe enough to affect daily function, but the trajectory is established.
The difference between hearing conservation and most other safety domains is that the "near miss" — the STS — is invisible without audiometric testing. No incident occurred. No one reported anything. The worker may feel fine. Only the audiogram reveals that the protective system has been inadequate.
STS follow-up rates in occupational health programs are notably poor. Research and OSHA enforcement data consistently show that the most commonly cited 1910.95 violation is failure to follow up on STS findings within the required 21-day window — not because employers are indifferent, but because the STS identification and notification workflow is often manual, slow, and decoupled from the testing event itself.
When audiometric testing is outsourced to a mobile van vendor, results typically take 2–4 weeks to return. By the time an STS is identified and the notification clock starts, the testing event is ancient history. The worker has been back in the noise environment for weeks, without any adjustment to their hearing protection or a conversation about what the audiogram found.
This is the structural failure: the near miss goes unacted upon, and the trajectory continues.
In a well-functioning hearing conservation program, an STS finding triggers an immediate, structured response — the same way a near miss in a high-hazard operation triggers an incident investigation and corrective action:
This is not a bureaucratic checklist. It is a genuine corrective action cycle triggered by an early warning signal — exactly the response any safety professional would apply to a near miss in any other hazard category.
The reason STS follow-up is so consistently poor in traditional programs is that the near miss signal — the audiometric change — is not delivered in real time. A testing event that returns results 3 weeks later, reviewed by a professional supervisor who is managing hundreds of records, does not produce the timely response that a near miss warrants.
Automated audiometric testing platforms change this. When testing is conducted in-house with immediate digital result upload, professional supervisor review can occur within hours rather than weeks. STS flags can be generated automatically. The 21-day notification clock starts from a position of days remaining, not hours.
The near miss gets treated like a near miss: promptly, specifically, and with corrective action while there's still time to matter.
Soundtrace's audiometric testing platform is built around this principle. Every audiogram is reviewed by a licensed professional supervisor. STS flags are generated automatically. The workflow from test to notification to follow-up documentation is structured to treat every threshold shift as the early warning signal it is.