 loss. It will soon become clear how well a company's hearing conservation program is protecting the hearing of its workers.
"OSHA should get a gold star for this one," comments Stephenson. "It opens up a whole new way to monitor what's happening to the hearing health of American workers."
It may also open a whole new set of challenges for employers with hearing protection programs.
Sidebar: The New Wave of Hearing Protectors
"There has been nothing new in hearing protection for 20 years, and suddenly there's a whole lot that's new," says Lee Hager, hearing loss prevention consultant for Sonomax Hearing Health Care, headquartered in Montreal.
NIOSH's Mark Stephenson agrees. He's most excited about electronic earmuffs that can amplify outside noise so those with impaired hearing can communicate or hear warning bells. The devices are equipped with "smart circuits" that sense when noise reaches a certain level so that the external microphone is turned off.
"These products are ideal for hearing-impaired workers in construction environments, where noise levels vary and communication is important," comments Stephenson.
Although these hearing protectors have come down in cost, their primary disadvantage remains their price: approximately $200 per unit, according to Mike Cimino, marketing director for Peltor Communications of North America, a manufacturer of electronic and two-way communication headsets. Peltor is part of the Aearo Co., wiheadquartered in Indianapolis.
Cimino says Peltor also produces models with built-in FM radios that are very popular with workers, increasing the chances the units will be used. Often employees will share the cost with employers. A more expensive version has a two-way radio that allows for communication with any number of other workers.
All three items are being used in construction and industrial settings, according to Cimino. "Manufacturing employment is dropping, which means communication in the workplace is more critical than ever because there are fewer people on the job."
Hager explains that Sonomax developed a new technology of instantly delivered custom-fitted earplugs. "What we do is manufacture a silicone balloon, place it in the ear canal, and inflate it with silica," he says. It is then possible to do a quantitative fit test of the device, and adjust it to match the worker's noise exposure.
The advantage of this is it avoids the danger of over-protection, a frequent cause of workers not using personal protective equipment. Hager says this new product addresses two other frequent problems in hearing protection programs: traditional protectors may not be properly fitted to the employee, or correctly worn.
Elliott Berger, senior scientist of auditory research at Aearo, a rival company, believes the Sonomax product has application in some noise environments. "But the current measurements of the effectiveness of this new product are under optimum conditions, and they have no data on what happens over the two-year life expectancy of the product," he says.
Natural sound technology is another option for those with impaired hearing working in lower noise environments (up to 92 dB), according to Berger. These devices have "flat attenuation" characteristics, which means they reduce noise equally at all frequencies. Traditional hearing protectors reduce high frequencies more than low, and this poses a problem since communication and warning devices tend to be high-frequency sounds.
Sidebar: OSHA Revises STS Recording Criteria
A Standard Threshold Shift (STS) is defined as a10 dB shift in hearing acuity. In a change that took effect at the beginning of this year, OSHA now requires the recording of an STS that has resulted in a total 25 dB level of hearing loss above audiometric zero, averaged over the frequencies at 2000, 3000, and 400 Hz.
Starting Jan. 1, 2004, OSHA will require employers to record an STS on the OSHA log in a separate column dedicated to hearing loss. For the first time, the federal government will be in a position to know the full extent of occupational hearing loss.