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ESH Manual Page: 4000: Industrial Hygiene

This Hearing Conservation program is established for the Sanford Underground Research Facility (“Sanford Lab”) to prevent overexposure to high noise levels and hearing loss.  


This program applies to all SDSTA employees who may be exposed to noise hazards above the action level.  


3.1. EHS Department

The EHS Department is responsible for:

  • Revising the hearing conservation program as needed;
  • Developing and implementing hearing conservation training;
  • Working with department directors/supervisors to: o  identify noise hazards,
    • conduct noise monitoring
    • establish appropriate noise controls;
  • Assuring that baseline and initial audiometric exams are performed;
  • Work with the Human Resources department to identify an appropriate medical monitoring provider for follow-up audiometric exams;
  • Report standard threshold shifts potentially caused by occupational noise to applicable authorities and stakeholders.

3.2. Department Directors/ Supervisors

Department Directors/Supervisors are responsible for:

  • Arranging for noise level assessments in areas under their control suspected to have noise levels that equal or exceed the 85 decibel TWA for noise exposure;
  • Ensuring employees working in their departments, that will be working in areas known to exceed the action level, are trained and enrolled in the Hearing Conversation Program;
  • Arranging for noise level assessments when conditions change and over exposure is suspected;
  • Considering noise levels when evaluating new equipment for purchase.
  • Alerting EHS to upcoming work requiring noise level assessments.

3.3. Sanford Lab Personnel

All Sanford Lab Personnel working in areas where the noise exceeds the action levels are responsible for: 

  • Using noise controls, including  personal protective equipment provided when working in high noise areas;
  • Completing hearing conservation training;
  • Receiving audiometric monitoring.

3.4. Project Managers

Project Managers are responsible for:

  • Reviewing proposed processes involving noise hazards with the EHS Department before installing new equipment; 
  • Informing contractors of Sanford Lab locations where noise exposures may exceed the action level. 
  • Informing Sanford Lab Personnel and/or the EHS Department of possible high noise exposures created by temporary contractor work that may affect other workplaces.
  • Enforcing hearing conservation requirements in their respective contracts.

3.5. Human Resources

The Human Resources department is responsible for:

  • Arranging for annual audiometric evaluations of all employees potentially exposed above the action level.
  • Maintaining records of annual audiograms for duration of employment + 20 years.
  • 3.6. Contractors and Personnel From Other Organizations

  • Contractors and laboratory personnel working onsite for an employer other than SURF are to follow their employer's hearing conservation programe which, at a minimum, must comply with the  requirements found in OSHA's 10 CFR 1910.95 - Occupational Noise Exposure Standard.


Action Level:  The OSHA action level for noise is defined as 85 dB(A) as an 8 hour time-weighted average.  However, an average of 85 dB(A) for more than 8 hours would result in a greater exposure than allowed by the OSHA standard.  Given the extended work shifts at Sanford Lab, expressing noise exposures as dose provides a better measure of exposure.  Thus a 50% noise dose will be used as the action level.

Audiometric testing:  The testing of a person's ability to hear sound at various frequencies. The test is performed with the use of electronic equipment called an audiometer. 

OSHA Noise Dose: OSHA defines noise exposures based on an 8-hour time-weighted integrated average of sound pressure levels (SPL) greater than 80 dB(A) where 8 hours at 90 dB(A) would result in 100% dose and every 5 dB increase in SPL doubles the dose.

Standard Threshold Shift: An average hearing shift in either ear of 10 decibels or more at the test frequencies of 2000, 3000 and 4000 Hertz.



The following monitoring measures will be taken to identify exposure groups that have a risk of noise exposure:  

  • Noise surveys have been and will continue to identify the areas where employee noise exposures exceed the OSHA 50% noise dose action level.
  • Additional monitoring will be conducted when changes in process, equipment, or controls suggest that noise exposures may have increased.
  • Each employee will be notified of their monitoring results. 
  • Further details for scheduled noise monitoring may be found in the SURF IH Monitoring Plan for the current fiscal year.


All SDSTA employees with an exposure to noise levels above the OSHA Action Level will be included in the hearing conservation program.  Appendix A lists the occupational roles in the hearing conservation program.  The hearing conservation program consists of the following elements:

  • Audiometric testing – an initial, baseline audiogram during the pre-employment screening process followed by annual audiograms taken to monitor potential hearing loss
  • Noise controls - control for noise will follow the hierarchy of controls established by OSHA. Control options include (in this order):
    • Elimination/Substitution;
    • Engineering Controls;
    • Administrative Controls; and
    • Personal Protective Equipment (PPE).
  • Training – hearing conservation training given annually; and
  • Recordkeeping – Any employee who experiences a Standard Threshold Shift of 25 dB or greater in audiometric testing will be entered on the OSHA 300 Recordkeeping log as a recordable illness.

Further information for each of the above elements is detailed in theSURF Hearing Conservation Program.


6.1. Standards

  • 29 CFR 1910.95:  Occupational Noise Exposure
  • 29 CFR 1926.52:  Occupational Noise Exposure
  • ACGIH TLVs and BEIs

6.2. Related Documents

  • Construction EHS Manual
  • FY-2015 SURF IH Monitoring Plan
  • Industrial Hygiene Policy 
  • SURF Hearing Conservation Program

6.3. Appendices

  • Appendix A:  Occupational Roles in the Hearing Conservation Program