30 CFR Part 62: MSHA Standards for

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30 CFR Part 62MSHA Standards for Occupational
Noise Exposure
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Noise Induced Hearing Loss

• Among the top ten work-related illnesses
  according to National Institute of Occupational
  Safety Health (NIOSH)
• 24,000 M/NM miners at risk under old rule (30 CFR
  56/57.5050)

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Mining - High Risk Occupations
Task Area Jobs Drilling/Cutting Wagon/Rotary
Drill, Jachammer, Stone Saw
Operators Haulage Truck, Bulldozer,
Front-End-Loader, Shovel, Dragline, Dredge
Operators Plant/Mill Plant Workers Crushing,
Sizing, Washing, Grinding,
Bagging Maintenance Laborer, Cleanup,
Mechanic, Welder
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What is Noise?

• Unwanted or undesired sound

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Sound is Vibrational Energy
Travels in Waves from a Source
FREQUENCY INTENSITY
Cycles per Second Hertz (Hz)
Decibels (dB)
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Characteristics that Determine the Degree of the
Noise Hazard1. Intensity (volume,
loudness)2. Frequency (pitch)3. Duration of
exposure
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Common Frequencies
Hertz (CPS)
63 125 250 500 1000 2000
4000 8000
-trombone-- ----------piccolo----------------
----truck---- -------compressed air
noise----------------
-------------speech---------------
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Decibel (dB)

• A unit of measure of sound pressure levels
• 20 times the common log of the ratio of the
  measured sound pressure level to the threshold of
  hearing _at_ 1000 Hz
• NOT SIMPLE MATH!!

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Relationship between intensity and
decibels for measuring hearing
dB Intensity 0 1 10 10
20 100 30 1,000
(1 thousand times) 40 10,000
50 100,000 60 1,000,000
(1 million times) 70 10,000,000
80 100,000,000 90 1,000,000,000
(1 billion times) 100 10,000,000,000
110 100,000,000,000 120 1,000,000,000,000
(1 trillion times) 130 10,000,000,000,0
00 140 100,000,000,000,000
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Common Sound Levels
Pain Threshold 140 dB Channel Burner 125
dB Chain Saw 120 dB Air-Track Drills 115
dB Large Haul Trucks 109 dB Bulldozers 107
dB Scrapers 104 dB Front-end Loaders 101
dB Rock crusher 94 dB Street Traffic 83
dB Normal conversation 60 dB Inside house
45 dB Soft Whisper 10 dB Threshold of
hearing 0 dB
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What Difference Does 5 Decibels Make?

• MSHA uses a 5-dB doubling factor as the basis of
  its regulations
• With every increase in exposure of 5 dB, the
  workers allowable time in an area is cut in
  half.
• 3 dB is the mathematically correct value is
  used for noise control engineering

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Permissible Noise Exposures
Duration per day Sound level (hours of
exposure) (dBA, slow response) 8 . . . . . . .
. . . . . . . . . . . . . . . . . . . . . 90 6
. . . . . . . . . . . . . . . . . . . . . . . . .
. . . 92 4 . . . . . . . . . . . . . . . . . .
. . . . . . . . . . 95 3 . . . . . . . . . . .
. . . . . . . . . . . . . . . . . 97 2 . . . .
. . . . . . . . . . . . . . . . . . . . . . . .
100 1-1/2 . . . . . . . . . . . . . . . . . . .
. . . . . . 102 1 . . . . . . . . . . . . . . .
. . . . . . . . . . . . 105 1/2 . . . . . . . .
. . . . . . . . . . . . . . . . . . 110 1/4 or
less . . . . . . . . . . . . . . . . . . . . 115
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Noise Measurement

• Expressed as a dose, or percentage of allowable
  limit, where 90 dB is the criterion 5 dB is
  the exchange rate
• TWA of 90 dB for 8 hours 100
• Measured on A scale slow response
• Either by dosimeter or sound level meter
• Personal sampling

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A Weighting (dBA)
50 HZ at 95 dB
5000 HZ at 76 dB
PERCEIVED AS EQUALLY LOUD BY THE HUMAN EAR
Adjust the dB Scale to Account for the Ears
Sensitivity to Different Frequencies
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The Human Ear

• The ear of an average, healthy, young adult can
  respond to frequencies in the range of 20 Hz to
  20,000 Hz
• The human ear is most sensitive to sounds of 1000
  Hz to 4000 Hz

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Anatomy of the Human Ear
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Transmission of Vibrations through Inner Ear
Long Waves (Low Frequency and Low Pitch) act at
top of the Cochlea
Oval Window
Ossicles
Short Waves (High Pitch and High Frequency) act
at the base of the Cochlea
Round Window
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Early Signs of Hearing Loss

• Ringing in the ears after a noisy activity
• Difficulty understanding what people say
• Turning up the volume of the TV or radio when
  others hear fine
• Not hearing background noises such as the
  telephone or doorbell

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Cross-section Normal Cochlea with Hair Cells
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Cross-section Damaged Cochlea Loss of Hair Cells
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Temporary Threshold Shift

• Hearing loss may initially be temporary
• Ear becomes fatigued by noise
• Recovers after a period of rest
• Pattern repeated for months years

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Leads to

• Permanent threshold shift
• Standard threshold shift (STS)
• Change in hearing threshold relative to the
  baseline - An average of 10 dB or more at 2K, 3K
  and 4K Hz in either ear.

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May Lead to

• MSHA Reportable Hearing Loss
• Change in hearing threshold relative to the
  baseline - An average of 25 dB or more at 2K, 3K
  and 4K Hz in either ear.
• Or, an award of compensation.

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Problems

• Cant give and receive instructions
• Cant hear warning signals
• Hard to communicate
• Cant hear sounds from machinery
• Reduced communication leads directly to accidents

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30 CFR Part 62 Compliance Levels

• Action level TWA8 of 85 dBA or 50 dose (80 -
  130 dBA)
• Permissible Exposure Level (PEL) TWA8 of 90 dBA
  or 100 dose (90 - 140 dBA)
• Dual Hearing Protection Level TWA8 of 105 dBA
  or 800 dose(90 - 140 dBA)
• 115 dBA maximum sound level

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What triggers an MSHA citation?

• Any miners full-shift exposure gt 2 dB above an
  allowable exposure level (i.e., 85, 90, 105)
• measured via personal dosimeter using A scale
  slow response
• Any exposure gt 2 dB above 115 dBA maximum sound
  level via SLM using A scale slow response
• 95 confidence limit

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Controlling Noise Exposure

• If MSHA (or operator) determines exposure exceeds
  PEL (TWA8 of 90 dBA or 100 noise dose), feasible
  engineering and administrative controls required
  (if capable of achieving significant reduction).
• This requirement applies even if the final noise
  level continues to exceed the PEL.
• In addition to engineering and administrative
  controls, adequate hearing protectors also
  required.

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Feasible Control Significant Reduction

• Feasible Control means
• The control reduces exposure.
• The control is economically achievable (costs
  proportionate to expected benefits).
• The control is technologically achievable (need
  not be off-the-shelf, but must have realistic
  basis in present technology).
• Significant Reduction means a reduction of3 dB
  or greater.

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Noise Reduction Methods

• At the Source- Select quiet equipment- Reduce
  speed, impact or impulsive force in machines
• In the Transmission Path- Separate noise and
  receiver (booths/cabs)- Use sound absorbing
  materials
• At the Receiver- Reduce exposure time- Alter
  work schedules- Hearing protective devices (last
  resort)

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Summary Actions Required By Operator

Section
Condition
Action Required
62.120 TWA8 lt 85 dBA No action
required 62.120 TWA8 ³ 85 dBA, Enroll
miner in HCP per but 90 dBA
62.150, HP use optional 62.130 TWA8 gt 90
dBA Use all feasible engrng
and/or admin controls enroll miner
in HCP ensure use of HP post
provide any admin
controls 62.140 TWA8 gt 105 dBA Ensure
use of Dual HP all 62.120 and 62.130
actions
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System of monitoring

• Operator must establish a system of monitoring
  that evaluates each miners exposure to determine
  continuing compliance
• Evaluation must reflect a full work shift
• Operator must notify the miner of results and any
  proposed actions within 15 days if TWA8 of 85 dBA
  or 50 dose or higher is measured

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What is a system of monitoring?

• A way of relating the miners daily noise dose
  to a measurable parameter, such as- Hours
  worked- Tonnage produced or consumed- Other
  data
• Expressed as dose where 8 hours _at_ 90 dBA or
  100 dose.

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Who is covered by the system of monitoring?

• The system of monitoring must provide an initial
  exposure assessment for all miners on site
• It must ensure continuing compliance of all
  miners exposures with the standard (Both Action
  Level and PEL)

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Does the operator have to do noise monitoring?

• No - the operator can base the system of
  monitoring on exposure predictions (i.e., other
  data)
• The operator can protectively place all miners in
  the HCP

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What Other Data ?

• MSHAs or other historical monitoring (available
  from MSHA Web Page)
• Representative personal monitoring
• Manufacturers information (e.g., cab noise
  levels in a Front-End-Loader)

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When does this have to be done?

• The standard was effective 9/13/00 - a year after
  publication.
• Exposure assessments for existing operations were
  to be completed by then.
• Complete audiometric testing by 3/13/01 or
  9/13/01
• If using mobile van option

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What are the operators responsibilities if the
miners are protectively placed into the HCP?

• All provisions of the HCP apply
• This includes notification, provision of PPE,
  audiograms, initial training, recordkeeping
• Within the established deadlines
• Evaluate exposures for compliance with PEL!!!

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Who should be included if the operator elects to
sample ?

• A least one miner as a representative of each
  exposure group (e.g., allEuclid R-50 haul truck
  drivers)
• Representative monitoring assumes that all miners
  doing the same operation with the same equipment
  have the same exposure

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Do I have to sample for the whole shift?

• No - But, all exposure models have to reflect the
  miners full-shift exposure
• As long as the exposure interval is
  representative of the whole days exposure you
  can simply adjust for the rest

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How?

• The mine operator can assume that the percent
  noise dose is accumulated in a predictable
  fashion
• For example
• 40 in 5 hours 8 dose per hour
• Therefore, a 12-hour shift _at_ 8 dose per hour
  96 dose per shift
• MSHA inspectors cant assume - they must measure
  miners actual full-shift dose!

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Hearing Conservation Program

• If AL (or higher) is exceeded a Hearing
  Conservation Program that includes the following
  must be in place (or instituted)- A system of
  monitoring- Provision use of PPE- Audiometric
  Testing- Training- Recordkeeping (i.e.,
  monitoring results, notifications, audiograms,
  training certification, etc.)
• Or if miners are protectively placed into HCP

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Hearing Protectors

• Provided by mine operator at no expense to miner
  (in HCP) including replacements
• Choice of 2 muff 2 plug types
• Maintained fitted per manufacturers
  instructions
• Voluntary use lt PEL, Mandatory at or above
• Required until baseline audiogram or if an STS
  has been detected

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Hearing Protection

• IF WORN CORRECTLY FITTED PROPERLY- Effective
  within limits of bone conduction transmission
  through absorbing material- Comfortable fit
  more important than high NRR

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Audiometric Testing

• Under supervision of physician, audiologist, or
  qualified technician
• Initial within 6 months of entry into HCP (or 12
  months if a mobile van is used)
• Annually (thereafter, as long as in HCP)
• Voluntary on the miners part
• Initial, annuals, and followups at no cost to
  miner
• unless not occupationally related

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Test Procedures

• Must use scientifically valid procedures (OSHAs
  specified procedure is OK)
• Pure tone, air conduction, hearing threshold, _at_
  500, 1000, 2000, 3000, 4000, 6000 Hz in either
  ear
• Operator provides results within10 working days
• Followup if indicated

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Understanding Audiograms
125 250 500 1K 2K
3K 4K 6K 8K
-10 0 10 20 30 40 50
BASELINE
ANNUAL
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Determine if Any Hearing Loss
125 250 500 1K 2K
3K 4K 6K 8K
-10 0 10 20 30 40 50
BASELINE
16
9
8
ANNUAL
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Determine if STS or Reportable
125 250 500 1K 2K
3K 4K 6K 8K
-10 0 10 20 30 40 50
BASELINE
16
9
8
16 9 8 33 33 / 3 11 Reportable ? NO
ANNUAL
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Determine if STS or Reportable
125 250 500 1K 2K
3K 4K 6K 8K
-10 0 10 20 30 40 50
BASELINE
16
9
8
16 9 8 33 33 / 3 11 Reportable ?
NO STS? YES
ANNUAL
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25 Years Later . . . Is there a Reportable
Hearing Loss?
Loss at 2K, 3K, and 4K (from Baseline to
Annual) 27 37 35 99 99 / 3
33 Reportable? YES
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What if the initial audiogram indicates
occupational hearing loss?

• On an initial (baseline) audiogram, this is not
  reportable, unless there is an award of
  compensation under the local workers
  compensation criteria
• File a 7000-1 if compensation is awarded

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What type of training?

• Within 30 days of enrollment in HCP, and every
  12 months thereafter, miner must be trained in
• effects of noise on hearing
• purpose and value of wearing HPDs
• advantages/disadvantages of HPDs
• care, fitting and use of HPDs
• general requirements of Part 62
• operator/miner responsibilities regarding
  controls
• purpose and value of audiometric testing

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Recordkeeping

• Mine Operator maintains a complete record for
  length of miners employment plus 6 months
• Copies available to MSHA (DOL) NIOSH (HHS)
  representatives within1 business day
• Copies of records available to miner, miners
  written designee, former miners, miners
  representatives within 15 days

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What happens when a new operator acquires the
mine?

• The baseline audiograms convey for the purposes
  of determining an STS or reportable hearing loss
• Doesnt apply to a successor operator hiring a
  miner who has never worked at that location

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What if the miner moves to a different mine?

• A miner transferring from one property to another
  may still have the same employer
• And may still meet the local criteria for
  workers compensation
• The current mine operator is responsible for
  submitting the 7000-1

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Can the operator hold the miner responsible for
the cost of replacement hearing protection?

• No - the cost for initial and replacement PPE is
  borne by the operator for each miner in the HCP
• Dont have to buy the most expensive if the loss
  rate is too high

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What about fitting maintenance of PPE?

• Any required PPE must be fitted maintained per
  manufacturers specifications
• Proper fitting is an indicator of good training

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Thank You