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

Topics Noise And Acoustics Motivating Workers Noise Reduction Reducing Costs for Hearing Loss

Noise + Acoustics 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 Is Permanent + 100% Preventable

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

Noise + Acoustics Worker’s Compensation In many countries, excessive noise is the biggest compensable occupational hazard. Cost of NIHL to developed countries ranges from 0.2 to 2% of its GDP. NIHL is on the rise globally. (Source: WHO)

Noise + Acoustics United States Statistics Most common occupational injury in the United States. 22 million US workers are exposed to hazardous noise at work on a daily basis. Approx. 8 million Americans suffer from NIHL. (Source: NIOSH, 2009)

Noise + Acoustics Non-OccupationalOccupational

Noise + Acoustics Noise Measurement Devices SOUND LEVEL METER Sound is measured immediately in a specific area PERSONAL DOSIMETER Sound “averaged” throughout day for sample employee/job IN-EAR DOSIMETER Collects personal noise dose – the only real measure of risk

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

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

How We Hear

The Auditory System Acoustical Mechanical Hydraulic Chem/Elec

How We Hear High Frequency Sounds of Speech S TH SH F H K T P CH

Noise Reduction Rating (NRR)

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

A test subject in the Howard Leight Acoustical Lab, San Diego, CA, accredited by the National Voluntary Laboratory Accreditation Program (NVLAP) 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

NRR Attenuation Number of test subjects Noise Reduction Rating – Determining an NRR NRR

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

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

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

Noise Reduction Rating Three New Labels LABELDESCRIPTION Conventional HPD  Perform lab test with subjects who fit the protector after brief training  Estimates the range of protection achieved by 20% and 80% of users Active Noise Reduction [ANR] Uses a Microphone-in-Real-Ear [MIRE] method to estimate protection Measured with ANR turned OFF and ON to show the additional attenuation from the ANR Level Dependent/ Impulse Noise Reduction Testing will occur over a range of impulse noise levels. Multiple tests to determine lower and upper ranges of impulse noise reduction Will include two ranges to identify attenuation for passive and active modes

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 Noise Reduction Rating Determining New NRR

New NRR (NR sa) Attenuation Number of test subjects % achieved > 26 dB 80% achieved > 20 dB 2826

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

Rating methods are based upon idealized laboratory testing NRR has been criticized for being too generous in its prediction of noise reduction [attenuation] Studies indicate that while some workers in real-world worksites achieve the NRR on the package or even greater protection, many workers do not This has led to a variety of inappropriate de-rating methods for hearing protectors Contributed too much confusion in knowing how to accurately estimate a HPD’s attenuation

Noise Reduction Rating Represents a range of expected protection Uses a new ANSI-standard lab testing to generate the attenuation ratings New NRR will provide an indication of how much attenuation minimally-trained users [the lower number] versus highly-motivated trained users [the higher number] can be expected to achieve For some hearing protectors, the spread of this range may be quite significant The New System: A Range

Noise Reduction Rating Current vs. Proposed NRR Current NRRProposed NRR Rating A single-number estimate of protection A high/low range of estimated protection Description of Rating Estimates the 98 th percentile of protection obtained by users when properly fitted Estimates the 80 th and 20 th percentile of protection obtained by users Test Protocol ANSI S [Experimenter Fit] 10 subjects for earplugs and earmuffs, HPDs fit by experimenter ANSI S Method A [Supervised Subject-Fit] 20 subjects [for earplugs] or 10 subjects [for earmuffs], HPDs fit by subject after brief training

Noise Reduction Rating Current vs. Proposed NRR Current NRRProposed NRR Application Intended for use with dBC noise measurements. Requires a 7 dB correction for use with dBA noise measurements. Can be applied directly to dBA noise measurements De-Rating Various de-rating schemes promulgated by various organizations [including OSHA] Designed to be used with no required de-rating Retesting Currently, no retesting of HPDs required Periodic retesting of HPDs required every 5 years

Noise Reduction Rating NRR Labels The proposed EPA regulation addresses for the first time the rating of non-standard hearing protectors, such as Active Noise Reduction [ANR] or level-dependent [or impact noise] protectors Under the old labeling requirements, these specialized protectors were rated with a low NRR, simply because they were not tested in the higher noise ranges where their noise reduction capability is activated EPA has included these types of hearing protectors in its new labeling regulation so that purchasers can make informed choices

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%

1. FIT 2. WEAR TIME A worker who selects an earplug with an NRR of 30 effectively reduced his 8-hour NRR to just … but then removes that HPD for just … 30 dB 5 min 10 min 30 min 15 min 26 dB 24 dB 22 dB 18 dB In noise exposures, small intervals of no protection quickly void large intervals of adequate protection. Noise Reduction Rating Factors in Achieving the NRR

Noise Reduction Rating What Can I Do Now? Evaluate Noise Spectra to determine if spectral balance corrections will be necessary Update HC Training Program on proper fit of hearing protectors. Hold a “Toolbox Training” and hold a refresher fit training session. Although the new labeling regulation takes effect whenever the final rule is published by the EPA, there are a number of actions you can take now to prepare your Hearing Conservation Program for the change.

Noise Reduction Rating What Can I Do Now? Evaluate Current HPD Selection to determine whether they are appropriate for your noise environment. Use the Howard Leight Hearing Protector Selector for recommendations. Howard Leight Hearing Protector Selector Upgrade to One-on-One Training research studies confirm that one-on-one training is superior to group training

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

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

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!

Reducing Costs of Hearing Loss

JurisdictionOneEar (Max) Both Ears (Max) Comments AL$11.7k (53 wks) $35.9 (163 wks) + aids, *NMER FL$9k$52k+ aids, *NMER GANone150 wks MS$11.2k$42k+ aids, *NMER Sample HL Compensation* *Source: AIHA Noise Manual *NMER= No minimum exposure required

Reducing Costs of Hearing Loss JurisdictionOne Ear (Max) Both Ears (Max) Comments NC$37.2k$80k+ aids SC$38.7 (80 wks) $80k (165 wks) *NMER TN$38.6k$77.2k+ aids DOL -LSA52 wks200 wks+ aids Sample HL Compensation* *Source: AIHA Noise Manual *NMER= No minimum exposure required

Indicators for Hearing Loss Reducing Costs of Hearing Loss Standard Threshold Shift Temporary Threshold Shift Recordable Hearing Loss Dosimetry In-Ear Dosimetry Personal Attenuation Level (PAR) Hearing Loss Compensation

Lagging Indicators vs. Leading Indicators Reducing Costs of Hearing Loss

Indicators for Hearing Loss Reducing Costs of Hearing Loss Standard Threshold Shift Temporary Threshold Shift Recordable Hearing Loss Dosimetry In-Ear Dosimetry Personal Attenuation Level (PAR) Hearing Loss Compensation

Fit Testing In-Ear Dosimetry Reducing Costs of Hearing Loss

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 occupational hearing loss

Reducing Costs of Hearing Loss

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

Preventive Action After NIHL 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 Months Audiometric test Retest Notification Reducing Costs of Hearing Loss In-ear dosimetry “worst case” scenario … 1 Day

In-ear dosimetry 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 Reducing Costs of Hearing Loss

Real-Ear Attenuation at Threshold (R.E.A.T.) Loudness Balance ( Real-Ear Attenuation Above Threshold ) Microphone in Real-Ear (M.I.R.E.) In-Ear Dosimetry Reducing Costs of Hearing Loss

AudiometricFitCheckEARfitVeriPRO REAT MIREREAAT Sound booth Very Quiet Room Quiet RoomAnywhere PAR Derived PARPAR Any earplug Selected modified earplugs Any earplug Special training required Anyone can perform Ear plug fit-testing methods

OSHA Alliance: Best Practice Bulletin Additional Information Reducing Costs of Hearing Loss

"I know how to better fit my earplugs now." "I was amazed with the results after being shown the proper way to use earplugs. "Learned A LOT about best earplugs for me" "I found a more comfortable fit. It was very beneficial." "Very glad I did the fitting test. Now I know the correct way to fit my ear plugs.” "Recently had threshold shift" "Found better earplugs" Field Verification – Fit-Testing "Feel like am protected now!" "I had no idea I was not using my earplugs correctly."

“How well can users predict their attenuation after a short fit-testing training session?" Pre and Post-Test Fit-Testing as a Training Tool

“How much noise do you think your earplugs block?” Pre and Post-Test Fit-Testing as a Training Tool Self-Efficacy 76% (13 of 17) judged attenuation as HIGHER post-test

Fit-Testing as a Training Tool Data show improved PARs! Results InitialRE=19 LE=22 Final RE=29 LE=27 Average improvement 7.5 dB

Are you better able to assess the effectiveness of your earplugs after VeriPRO fit-testing? No MaybeNo change Improved Yes Pre and Post-Test Fit-Testing as a Training Tool Post-Test 64% (11 of 17) rated their ability HIGHER post-test

Initial Ability Don't know how Not good I do OK Pretty good Expert Fitter Post-Test Ability Pretty good I do OK Expert I do OK Pretty good Expert Not good Pre and Post-Test Fit-Testing as a Training Tool

Pre and Post-Test Fit-Testing as a Training Tool Ability to Predict Noise Reduction Within 5 dB category +/- 7.5 dB (one Category off) +/ dB (2 categories off) Number of Ears (Each subject estimated atten. for each ear) 56% 32% 12%

Published NRR 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 Reducing Costs of Hearing Loss

Published NRR Trying a second earplug often improves attenuation REDUCING COSTS / CLAIMSReducing 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) Reducing Costs of Hearing Loss

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 Reducing Costs of Hearing Loss Tools for HCP Prevention Metrics

Off-job + On-job = STS Reducing Costs of Hearing Loss

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

Frequency in Hz Attenuation in dB Max Poor Fit NRR = 0dB Max Good Fit NRR = 33dB Good Fit vs Bad Fit

Training + Motivation

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? Training + Motivation Personalize Hearing Loss

Training + Motivation Training Materials atl.grc.nasa.gov/HearingConserv ation/Resources/index.htmlatl.grc.nasa.gov/HearingConserv ation/Resources/index.html Demonstrate Future Risk

Training + Motivation Send Clear Message On + Off Job HC Part of Everyday Life Include recreational hearing conservation in annual training Provide extra HPDs for home use Promote Hearing Conservation at company/family events

Training + Motivation Remove Barriers to HPD Use Make HPDs Available Highlight “where to find HPDs” in annual training Make sure HPDs are well- stocked and accessible Include group of workers in selection process for increased acceptance Offer wide variety to match comfort, job requirements

Hearing Loss Due To Noise Exposure Is … Painless Permanent Progressive … and very Preventable! Training + Motivation