Environmental Engineering Reference
In-Depth Information
employees. who. are. exposed. to. an. action. level. of. 85. dBA. or. above,. mea-
sured.as.an.8-hour.TWA..The.audiometric.testing.program.follow-up.should.
indicate. whether. the. employer's. hearing. conservation. program. is. prevent-
ing. hearing. loss.. A. licensed. or. certiied. audiologist. (specialist. involved. in.
evaluation.of.the.hearing.function),.an.otolaryngologist.(physician.special-
izing.in.the.diagnosis.and.treatment.of.disorders.of.the.ear,.nose,.and.throat),.
or.a.physician.must.be.responsible.for.the.program..Both.professionals.and.
trained. technicians. may. conduct. audiometric. testing.. The. professional. in.
charge.of.the.program.need.not.be.present.when.a.qualiied.technician.con-
ducts. tests.. The. professional's. responsibilities. include. overseeing. the. pro-
gram.and.the.work.of.the.technicians,.reviewing.problem.audiograms,.and.
determining. whether. referral. is. necessary.. The. employee. needs. a. referral.
for. further. testing. when. test. results. are. questionable. or. when. problems. of.
a.medical.nature.are.suspected..If.additional.testing.is.necessary.or.if.the.
employer.suspects.a.medical.pathology.of.the.ear.is.caused.or.aggravated.by.
the.wearing.of.hearing.protectors,.the.employee.shall.be.referred.for.a.clini-
cal.audiological.evaluation.or.otological.exam,.as.appropriate..There.are.two.
types.of.audiograms.required.in.the.hearing.conservation.program:.baseline.
and.annual.audiograms.
.
3.. The. baseline. audiogram. is. the. reference. audiogram. against. which. future.
audiograms.are.compared..Baseline.audiograms.must.be.provided.within.
6. months. of. an. employee's. irst. exposure. at. or. above. an. 8-hour. TWA. of.
85 dBA..An.exception.is.the.use.of.mobile.test.vans.to.obtain.audiograms..
In.these.instances,.baseline.audiograms.must.be.completed.within.1.year.
after.an.employee's.irst.exposure.to.workplace.noise.at.or.above.a.TWA.of.
85.dBA..Employees,.however,.must.be.itted.with,.issued,.and.are.required.
to. wear. hearing. protectors. for. any. period. exceeding. 6. months. after. their.
irst. exposure. until. the. baseline. audiogram. is. obtained.. Baseline. audio-
grams.taken.before.the.effective.date.of.the.hearing.conservation.program.
(April 7,.1983).are.acceptable.baselines.if.the.professional.supervisor.deter-
mines. that. the. audiogram. is. valid.. Employees. should. not. be. exposed. to.
workplace.noise.for.14.hours.preceding.the.baseline.test;.however,.appro-
priate.hearing.protectors.can.serve.as.a.substitute.for.this.requirement.and.
can.be.worn.during.this.time.period.
.
4.. Annual. audiograms. must. be. conducted. within. 1. year. of. the. baseline.. It.
is.important.to.test.hearing.on.an.annual.basis.to.identify.deterioration.in.
hearing.ability.so.that.protective.follow-up.measures.can.be.initiated.before.
hearing. loss. progresses.. Annual. audiograms. must. be. routinely. compared.
to. baseline. audiograms. to. determine. whether. the. audiogram. is. valid. and.
to. determine. whether. the. employee. has. lost. hearing. ability,. that. is,. if. a.
standard.threshold.shift.(STS).has.occurred..An.STS.is.an.average.shift.in.
either.ear.of.10.dBA.or.more.at.2,000,.3,000,.and.4,000.hertz..An.averaging.
method.of.determining.STS.was.chosen.because.it.diminished.the.number.
of.persons.falsely.identiied.as.having.STS.and.who.were.later.shown.not.to.
have.had.a.change.in.hearing.ability..Additionally,.the.method.is.sensitive.
enough.to.identify.meaningful.shifts.in.hearing.early.on.
