Hearing Conservation Theresa Y. Schulz, PhD. Lt. Col. USAF (ret.)

1. Hearing ConservationTheresa Y. Schulz, PhD.Lt. Col. USAF (ret.)

2. Topics Hazardous Noise Motivating Workers Noise Reduction/Attenuation Reducing Costs for Hearing Loss

3. Hazardous Noise Is Permanent + 100% Preventable • Noise-Induced Hearing Loss • Causes no pain • Causes no visible trauma • Leaves no visible scars • Is unnoticeable in its earliest stages • Accumulates with each overexposure • Takes years to notice a change

4. Hazardous Noise Noise-induced hearing loss is the most common permanent and preventable occupational injury in the world. World Health Organization

5. Hazardous Noise Non-Occupational Occupational

6. NOISE AND ACOUSTICS ~ Hierarchy of Controls Hazardous Noise Confirmed Ototoxics Ethyl Benzene Lead and inorganic compounds (as Pb) Styrene Toluene Trichloroethylene PossibleCarbon disulfide n-Hexane Xylene • Synergistic Ototoxics • Carbon Monoxide • Hydrogen Cyanide NOISE • Ototoxic Chemicals • Ototoxic by themselves • Synergistic effect with noise • Large differences in sensitivity • Recommend: increased frequency of audiometric testing

7. NOISE AND ACOUSTICS ~ Hierarchy of Controls Hazardous Noise - Hierarchy of Controls • ADMINISTRATIVE CONTROLS • Rotate Workers • Extended Breaks • 2nd/3rd Shift PERSONAL PROTECTIVE EQUIPMENT • ENGINEERING CONTROLS • Buy Quiet • Vibration Pads • Enclosures • Barriers • Isolation

8. Noise Reduction Rating(NRR)

9. Noise Reduction Rating • How much noise is reaching the ear of the worker ? Noise Level =100 dB Noise Reduction Rating =30 dB That is completely unknown … (55 – 104 dB)

10. 0 dB 0 dB >33 dB EAR #1 EAR #2 EAR #3 How much protection?

11. Noise Reduction Rating Frequency in Hz 1000 2000 3150 4000 6300 8000 250 500 125 90 Max Good Fit NRR = 33dB Max Poor Fit NRR = 0dB 80 70 60 Attenuation in dB 50 40 30 20 10 0 -10 Good Fit vs Bad Fit

12. Noise Reduction Rating • Noise Reduction Rating • A laboratory estimate of the amount of attenuation achievable by 98% of users when properly fit • A population-based rating ― some users will get more attenuation, some will get less The NRR is only a population estimate, not a predictor of individual attenuation.

13. Noise Reduction Rating – Determining an NRR • 10 human subjects tested in a reverberant room • Tested with ears open/occluded at nine frequencies • Each subject tested 3x • NRR calculated to be population average A test subject in the Howard Leight Acoustical Lab, San Diego, CA, accredited by the National Voluntary Laboratory Accreditation Program (NVLAP)

14. NRR Noise Reduction Rating – Determining an NRR NRR 5 4 Number of test subjects 3 2 1 26 28 30 32 24 22 14 18 20 19 23 25 27 Attenuation

15. Noise Reduction Rating Real user attenuation <0 to 38 dB Real-World Attenuation≠ NRR 192 users of a flanged reusable earplug ~ 27 NRR 50 NRR = 27 Multiple-Use Earplug 40 Retraining and refitting resulted in an average 14 dB improvement for this group 30 Attenuation in dB 20 10 0 -10 From Kevin Michael, PhD and Cindy Bloyer “Hearing Protector Attenuation Measurement on the End-User”

16. Noise Reduction Rating • De-Rating Methods OSHA NRR ÷ 2 (feasibility of engineering controls) NIOSH Earmuffs NRR – 25% Formable Earplugs NRR – 50% All Other Earplugs NRR – 70% CSA Class A up to 100 B up to 95 C up to 90 Fit Test

17. Noise Reduction Rating • Noise Reduction Rating • The EPA recently made an announcement about a proposed change to the Noise Reduction Rating [NRR] • This is the first change in hearing protector regulation in nearly 30 years

18. Noise Reduction Rating • Determining New NRR • 20 human subjects tested in a simulated industrial room • Subject trained then fits their own earplugs • Tested with ears open / occluded at 9 frequencies • Each subject tested 2x • NRR calculated to be population average

19. New NRR (NRsa) 80% achieved > 20 dB 20% achieved > 26 dB 5 4 Number of test subjects 3 2 1 24 22 11 14 18 20 26 28 30 33 19 23 25 27 Attenuation

20. Noise Reduction Rating 20th % Proficient Users 80th % Minimally-trained Current NRR Label Mock-up of New Label

21. Noise Reduction Rating • How to Apply the New Label Two-number range displays the estimated protection achievable by minimally-trained users [80%] versus proficient users [20%]. A wider range indicates greater variability in the fit of that HPD. Smaller ranges indicate more consistency of fit. For example, earmuffs will usually have a tighter fitting range than earplugs, and may have a smaller NRR range. 80% 20%

22. Noise Reduction Rating • Earplug Fit Testing • Provides an accurate,real-world picture of your employees’ hearing protector effectiveness. • Identify if your employees are: • Receiving optimal protection • Require additional training • Need to try a different earplug style

23. Noise Reduction Rating • Earplug Fit Testing • As a problem solver: • Derating Schemes • One-on-One Training • HPD Selection • NRR Change

24. Noise Reduction Rating • In-Ear Dosimetry • As a Problem Solver • Continuously monitors in noise level at the workers ear • The only true measure of the hazard!

25. Reducing Costs of Hearing Loss

26. Reducing Costs of Hearing Loss • Indicators for Hearing Loss: • Standard Threshold Shift • Temporary Threshold Shift • Recordable Hearing Loss • Dosimetry • In-ear Dosimetry • Personal Attenuation Level (PAR) • Hearing Loss Compensation

27. Reducing Costs of Hearing Loss Lagging Indicators vs. Leading Indicators

28. Reducing Costs of Hearing Loss • Indicators for Hearing Loss: • Standard Threshold Shift • Temporary Threshold Shift • Recordable Hearing Loss • Dosimetry • In-ear Dosimetry • Personal Attenuation Level (PAR) • Hearing Loss Compensation

29. Reducing Costs of Hearing Loss In-Ear Dosimetry Fit Testing

30. In-ear dosimetry measures/records worker’s actual noise dose, with and without protection Provides real-time monitoring and alerts when worker approaches/exceeds safe limits Only metric with direct potential to measure and prevent further progression of occupationalhearing loss

31. Reducing Costs of Hearing Loss

32. Research > Alcoa Intalco Works Reducing Costs of Hearing Loss • Mean Hearing Threshold (2k, 3k, 4kHz): 2000 – 2007 (N = 46) • Employees using continuous in-ear dosimetry starting in 2005

33. Preventive Action After NIHL Reducing Costs of Hearing Loss • Audiometric test •Retest •Notification 0 2 4 6 8 10 12 14 16 Months In practice, an OSHA-recordable STS is not a preventive action It is documentation of a hearing loss after the fact. How soon will an employee suffering NIHL be re-fit / re-trained ? “Best case scenario” per Hearing Conservation Amendment In-ear dosimetry “worst case” scenario … 1 Day

34. In-ear dosimetry as a Problem Solver Reducing Costs of Hearing Loss In-ear monitoring as a Problem Solver • Employees with Documented Noise-Induced Hearing Loss or Standard Threshold Shift [STS] • Employees At-Risk for NIHL • Employee Training + Sampling • Dual-Protection/Extreme Noise Exposure • Engineering Controls

35. Field Verification – Fit-Testing Real-Ear Attenuation at Threshold (R.E.A.T.)

36. Field Verification – Fit-Testing Loudness Balance (Real-Ear Attenuation Above Threshold)

37. Field Verification – Fit-Testing Microphone in Real-Ear (M.I.R.E.)

38. Field Verification – Fit-Testing * Commercially available

39. Reducing Costs of Hearing Loss OSHA Alliance: Best Practice Bulletin www.hearingconservation.org Additional Information www.howardleight.com

40. Reducing Costs of Hearing Loss Published NRR

41. Reducing Costs of Hearing Loss Personal Factors Gender Age Years in Noise Ear Canal Size Familiarity Model of Earplug Program Factors # Group Trainings # Personal Trainings

42. REDUCING COSTS / CLAIMS Reducing Costs of Hearing Loss Published NRR Trying a second earplug often improves attenuation

43. Reducing Costs of Hearing Loss Earplug fit-testing as a Problem Solver • Training tool for noise-exposed workers • Train-the-trainer tool • Follow-up on significant threshold shifts in hearing • Documentation of HPD adequacy • Assessment of overall HCP effectiveness • Match HPD to worker’s specific noise level • Selection of appropriate HPDs for new hires • Benefits per Best Practices Bulletin (OSHA Alliance)

44. Now: Integrated Bluetooth, In-Ear, ATEX Sensear Phonak CavCom Howard Leight Communication Solutions

45. Reducing Costs of Hearing Loss Intelligent HPDs as a Problem Solver • Hearing Protection vs Situational Awareness vs. Communication • Improper use of HPDs (removal) • Accidents due to poor speech intelligibility • Extreme noise environments • Double protection required • Compatibility with other PPE

46. Protection against continuous, intermittent, and impulse noise Connect w/two-way communication radios Digital sound processing Adaptive talk-through Situational awareness Active Noise Reduction Fit check for protection Communication Solutions

47. Reducing Costs of Hearing Loss Tools for HCP Prevention Metrics • PROS • Estimate Measure • NRR obsolete • Fulfills OSHA compliance • Eliminates need for de-ratings • Medico-legal cases • Delineates non-occupational • Eliminates double protection • Provides employee feedback • (HPD Inventory control) • CONS • Cost • Time Investment • Not standardized

48. Training + Motivation

49. Training + Motivation Common Objections to Wearing HPDs “I already lost some of my hearing, so why should I wear them?” “Won’t I get an ear infection?” “Hearing protectors are uncomfortable to wear.” “I don’t need them! I am used to the noise.” “I can’t hear my co-workers if I wear them.” “Can I hurt my eardrums if I insert an earplug to deeply.” “I can always get fit with a hearing aid.” “My machine sounds different.”

50. Training + Motivation • Personalize Hearing Loss • Show, Don’t Tell • Provide copy of annual audiogram to worker • Use personal examples to demonstrate consequences of hearing loss • Ask questions: • What is your favorite sound? • What sound would you miss the most if you couldn’t hear? • What sounds connect you to people and your environment?