Can You Hear Me Now’

Despite numerous technological advances in the metalworking industry over the past twenty years, noise continues to be a major hazard, with levels at typical shops easily exceeding 100 dB.

Excessive noise, according to a recent World Health Organization study has “many adverse effects, including elevated blood pressure, reduced performance, sleeping difficulties, annoyance and stress, tinnitus, noise-induced hearing loss (NIHL) and temporary threshold shift.” Of these, noise-induced hearing loss is the most significant. Damage to the delicate hearing mechanisms of the inner ear caused by excessive noise accumulates slowly over time and cannot be repaired: noise-induced hearing loss is permanent.

It is also 100 percent preventable. OSHA’s Occupational Noise Exposure Standard and Hearing Conservation Amendment (29 CFR 1910.95) stipulates that employers “shall administer a continuing, effective hearing conservation program” when worker exposure levels “equal or exceed an eight-hour time weighted average sound level (TWA) of 85 dBA.”

In this article, we will summarize the key elements of an OSHA-approved Hearing Conservation Program.

NOISE MONITORING/AUDIT

Before an effective hearing conservation program can be established, you need to accurately characterize the noise environment and identify affected employees. OSHA requires monitoring when noise levels equal or exceed 85 dBA TWA (Time Weighted Average at 8-hours), including all continuous, intermittent and impulsive sound. A good rule of thumb is that if you must raise your voice to be heard by someone an arm’s length away, the noise level is probably hazardous.

Monitoring requires sound level meters which sample area noise levels, and dosimeters which record an individual’s noise exposure. While area sampling provides a good understanding of general noise levels throughout a facility, personal sampling documents a worker’s complete exposure during the course of their work day. Re-measurement is required when noise levels change “significantly,” though it’s a good idea to remap affected areas annually regardless of change.

Posting a “noise map” of a facility can help give workers a visual reference to sites where hearing protection devices (HPDs) must be worn. Posting specific decibel levels in work areas is also an effective way to identify the need for HPDs and help workers select the right protector for their application.

Concurrent with initial or annual monitoring, a full program audit should be conducted. This should focus not only on noise hazards but on a top down review of the management, administrative, and material resources available to control them. Studies have shown, for example, that employees who fail to wear hearing protectors or who tend to skip hearing tests, tend to work for supervisors who do not take hearing conservation seriously. An audit can help make sure the management structure is in place to enforce program requirements. (A free guide of practical tips, “Best Practices in Implementing a Hearing Conservation Program,” can be downloaded from www.howardleight.com)

AUDIOMETRIC EVALUATION

OSHA requires all new employees to undergo an audiometric test within six months of employment. All noise-exposed workers must also be tested on an annual basis. Individual results are compared from year to year to determine if hearing has remained stable.

Audiometric testing must be conducted by a trained professional, and can be done in-house or outsourced to industrial clinics and audiology practices. Many practices offer mobile testing services that are very economical, and can work around employees’ schedules to minimize worker downtime. One source list of competent mobile testing services is maintained by the National Hearing Conservation Association (303/224-9022 or nhca@gwami.com).

A good idea is to use an audiometric testing provider who can combine required employee training with the annual audiometric test. One-on-one training at the time of testing is often more effective than group training. Also, make certain your testing service provides the required baseline comparisons, and that the follow-up reports are understandable.

While audiometric technicians can administer an audiogram, only audiologists, otolaryngologists and physicians may interpret the test results. Often these providers can send out any notifications as required by the OSHA standard. Research has shown that when employees receive copies of their audiograms or explanations of the results at the time of testing, rates of noise-induced hearing loss in that workforce decrease.

ENGINEERING AND ADMINISTRATIVE CONTROLS

OSHA’s first line of defense against hazardous noise is to implement feasible engineering or administrative controls to minimize its impact. These can include sound dampening enclosures around noisy machines, partitioning noisy areas, or scheduling work or personnel to minimize exposure.

When purchasing new equipment, companies should seek to “buy quiet” by seeking or specifying machinery with low noise levels. Providing a clean, quiet, but conveniently located break and lunch area can help reduce employee exposure, and keeping communication channels open regarding noise can also help identify new ways to reduce exposure.

PERSONAL HEARING PROTECTION

If engineering and administrative controls fail to reduce noise levels below 85 dBA, 29 CFR 1910.95 requires that employers provide exposed employees with a “variety of suitable hearing protectors” ? i.e., earplugs or earmuffs ? at no charge to the employee. Workers with normal hearing are required to wear hearing protectors (HPDs) when exposure levels reach 90 dBA, while workers with an identified hearing loss must wear HPDs when noise exposure reaches 85 dBA.

While OSHA does not define the term “variety,” it is a good practice to provide a robust selection of HPDs. Everyone’s ears are different, and one earplug or earmuff style may not be comfortable for an entire workforce. A wide variety of HPDs are available to meet specific applications and/or worker preferences, ranging from single and multiple-use earplugs in different styles and materials, to banded earplugs that can be inserted quickly during intermittent noise, to dielectric and cap-mounted earmuffs.

Compliance in wearing hearing protection can be as simple as ensuring an ongoing supply, or providing easily accessible dispensers. But sometimes, the barriers run deeper, and begin in the selection process. A recent NIOSH study examined the reasons why workers do not consistently wear hearing protectors. Though respondents came from several different countries and from many different industries, the results were quite consistent: the major obstacles to consistent hearing protector usage are interference with communication and/or with job performance, and comfort.

A number of hearing protectors are now available that address workers’ concerns of overprotection and communication interference.

Earplugs offer different attenuation ratings (NRRs) for different noise levels; others are made of special high-tech material which conforms to the shape of the wearer’s ear canal. Several earplugs and earmuffs have been designed to maximize communication through uniform attenuation, allowing wearers to hear important sounds (co-workers, warning signals, radio and communication systems, maintenance sounds from machinery) more naturally while still protecting from harmful noise levels.

Electronic earmuffs can also enhance communication by amplifying ambient sounds (including speech and warning signals) to a safe level, while protecting against louder, more damaging noise.

Other factors to consider in selecting appropriate hearing protection include size, compatibility with other personal protective equipment (hard hats and safety eyewear), and special job requirements (the need for corded earplugs, or high-visibility earmuffs, for example).

Many successful Hearing Conservation Programs actively involve noise-exposed workers in the selection process: a group of representative employees tries samples of a variety of hearing protectors being considered for purchase. This feedback proves valuable in obtaining employee buy-in, and in removing barriers that cannot be evaluated from viewing product specifications alone.

TRAINING AND MOTIVATION

To comply with the standard, all employees exposed to the 85 dBA Action Level must receive annual training, which includes information on: the effects of noise exposure; the use, selection and fitting of hearing protectors; and audiometric testing procedures.

Traditionally, this has been performed in group sessions, conducted by safety managers, industrial hygienists, safety nurses and other Hearing Conservation professionals using videos, posters and other educational and motivational materials. Hearing Conservation training helps employees recognize hazardous noise situations at work and at home, and encourages them to protect themselves appropriately.

However, recent studies on the real-world attenuation of hearing protectors worn on the job suggest that one-on-one training may be more effective. It has long been recognized that the best time to motivate employees to use hearing protection is immediately after their audiometric test, when they can actually see the results. But a recent study done by the Howard Leight Acoustical Laboratory has taken this idea further.

The study was conducted on over 100 employees at eight different facilities. Employees were tested during their standard shift. They were not pre-screened, and were tested with their own earplugs that they routinely wore on the job, with no modifications. The tested earplugs were from four different manufacturers, and employees received no training or coaching as part of the test. They were simply asked to insert the earplugs as they normally did on the job. No feedback or correction was offered if they fit the earplug incorrectly.

The results (Figure 1) showed a direct correlation between earplug fit and effective attenuation: fully one-third of employees achieved attenuation higher than published Noise Reduction Ratings (NRR) for their earplugs; another third achieved attenuation within 5 dB of those ratings; and one-third had attenuation that was more than 5 dB below published NRRs.

In identifying the factors that contributed to good earplug fit, and hence, good attenuation in use, only one-on-one training had a strong correlation. The more often an employee had received individual training in the proper use of hearing protectors, the higher the probability that employee would achieve a good fit.
An effective Hearing Conservation Program, then, should include a high proportion of individual fit training sessions. Group training should also include motivational materials to help make the case that employees are susceptible to noise damage, demonstrate the risk of hearing loss, and encourage employees to wear hearing protectors both on and off the job.

In addition to formal training, a good idea is to hang motivational and informational posters in common areas or near hearing protection sources. These can include fitting instructions, noise thermometers, and posters visually demonstrating the effects of NIHL. Many HPD manufacturers offer such posters for free or make them available online as PDFs. These can provide additional reinforcement on the importance of hearing protection and conservation.

RECORD KEEPING AND EVALUATION

The final component of OSHA’s Hearing Conservation amendment is about the employer’s responsibility to maintain all records and to evaluate the program’s effectiveness on a regular basis. Without accurate records, you have no way of assessing progress or rectifying problems. Thus, accurate records of noise exposure levels and of all audiometric tests must be kept.

And don’t forget to post a copy of OSHA’s hearing regulations at the worksite. Nearly three-fourths of OSHA’s recordkeeping violations in Hearing Conservation in the past five years were for simply not having a copy of the Hearing Conservation standard posted in the workplace. (Posters of the standard are available from several manufacturers, including Howard Leight at 800-430-5490.)

NIHL IS NOT JUST IN THE WORKPLACE

Finally, it should be noted that noise-induced hearing loss does not just happen in the workplace. Noise from a rock concert, lawnmower or chainsaw can cause just as much hearing damage as a lathe or grinding machine, and an effective Hearing Conservation Program should seek to make workers aware of all noise hazards. Include leisure-based activities in training sessions and encourage employees to take earplugs home. The added HPD expense will easily be offset by healthier, more productive employees.

Renee S. Bessette is the marketing manager for Sperian Hearing Protection, LLC, 7828 Waterville Road, San Diego, CA 92154, 800-430-5490, Fax: 401-232-3110, rbessette@SperianProtection.com, www.SperianProtection.com.