Operator Safety - Wastewater Operators - page 22

only as good as the seal they provide around the ear. In extremely noisy
environments it might be wise to recommend double hearing protection :
wearing both ear plugs and earmuffs at the same time.
Another important area that needs to be addressed in the plant
hearing conservation program is the designation of audiometric evalu-
ation procedures. OSHA requires employers with facilities where noise
exposure equals or exceeds an average of 85 dB over an 8-hour period to
provide their employees with audiometric testing. Wastewater treatment
plant safety officials can ensure that audiometric examinations are con-
ducted by either performing the tests themselves or by hiring a local
medical contractor to perform the tests. If the evaluation is conducted
in-house, the audiometric technician must be properly trained. NIOSH-
approved training centers offer audiometric technician or occupational
hearing conservationist training throughout the country. This training
usually can be completed in 3 days, and the trainee is not required to
have a medical background. Moreover, audiometric equipment is readily
available to purchase at reasonable prices. The plant safety person must
keep in mind that audiometric testing must be conducted in a noise-free
environment (e.g., in an audiometric testing booth).
Whatever audiometric testing approach the plant safety person
decides to implement, in-house testing or hiring a medical contractor,
the audiometric testing procedure has some requirements that are man-
datory. For example, each employee who might be exposed to noise lev-
els at or greater than 85 dB must be given a baseline audiometric test.
The audiometric test should be conducted only when the worker has not
been exposed to workplace noise for at least 14 hours. Testing must be
performed by a certified audiometric technician using a calibrated audi-
ometer (annual requirement) in an environment of less than 40 dBA. Six
months after receiving the baseline audiometric test, the worker should
be tested again and then annually thereafter. All new employees should
be given the baseline audiometric test within 6 months of their hire date.
Any worker who experiences a temporary or permanent threshold shift
should be retested within 60 days. A temporary threshold shift (TTS)
represents auditory fatigue caused by excessive exposure to noise. TTS
is transient but its presence is undesirable. A permanent threshold shift
(PTS), on the other hand, is a more serious hearing disability. As the
name implies, PTS can result in permanent loss of hearing acuity and
should be rigorously guarded against. If the follow-up audiometric test
suggests a permanent threshold shift rather than temporary threshold
shift, the worker must be referred to a physician for evaluation as to
whether or not the damage is permanent. All cases of occupational-
related hearing loss must be recorded on the OSHA Form 300 log, and
the plant's hearing conservation program must receive oversight guid-
ance from a licensed audiologist.
Because hearing loss is such a gradual process, it is often ignored
by the worker and the supervisor. This is why training is so critical. Like
all safety programs, the programs are only as good as the training that
is provided with the program. As part of a hearing conservation program
not only is training critical but so are supervision and management. An
effective hearing conservation program cannot be established without