Research on Noise Catching Attention

Measuring noise

Using specialized equipment, UNC graduate student Thea LaBere (right) measures noise levels produced by a chainsaw. LaBere, along with her faculty research mentor Deanna Meinke, have presented findings that emerged from the research to educate employers and employees regarding the potential noise hazards when operating equipment such as chainsaws, chippers, stump grinders and leaf blowers and the need for implementing hearing loss prevention programs.

Thea LaBere’s research on the noisy environment in which tree service workers operate is being heard loud and clear.

The graduate student’s study started to gain traction at this year’s City of Greeley Winter Tree Care annual workshop — where a year earlier LaBere’s request for research participants was made — after her faculty research mentor Deanna Meinke presented on her behalf the study’s findings.

Last summer, LaBere measured with specialized equipment the decibel levels of machinery while employees who volunteered for the project used them. The readings from the dosimeter proved that tree service workers are at increased risk for noise induced hearing loss, which is preventable.

Soon after the Greeley presentation, a national trade magazine approached to invite LaBere and Meinke to submit an article to a publication that reaches 28,000 arborists. The article, leaning on the study’s findings that hearing protection should be used when operating chainsaws, chippers, stump grinders, leaf blowers, water trucks, rotochoppers, tractors, brush/weed trimmers — equipment that can exceed permitted exposure levels issued by federal agencies — will be published this summer. A representative involved with the publication who advises on safety and regulatory compliance for the Tree Care Industry Association told LaBere that companies rarely use a dosimeter to measure noise exposure and that her research was the “missing key element” in advocating for employer compliance.

LaBere’s research has implications for anyone who uses such equipment. That means the homeowner who’s using a chainsaw to prune should take notice: exposure without protecting the ears can be hazardous.
LaBere recently took time to answer questions about her research:

Q: How’d you get started with the research?
TL: I got started with the research my first semester in grad school (2007) when I knew I wanted to focus on something that would make a difference in people’s lives. My grandfather has hearing loss from occupational and recreational noise exposure, and I have seen him suffer over the years with communication. I wanted to educate others on the importance of protecting your hearing and what hazardous noise exposure can do to your hearing and how it can detrimentally impact your quality of life.

Q: What surprised you most about the outcome of your research?
TL: That these workers were not educated on hazardous noise levels and the risk of losing their hearing. The workers did not know when they should be wearing their hearing protection (earplugs/earmuffs). As far as the outcome of noise level measurements, this was not surprising to me considering the equipment they are operating on a daily basis.

Q: How did you anticipate results would be received among workers and publications
TL: I didn’t expect that the workers would be as interested in learning about the outcome of their noise exposure as they were. Most of the workers wanted to know how loud their equipment was and what they should do to try and protect themselves and prevent noise-induced hearing loss (NIHL). They were genuinely interested in the research. Several of the employers have requested the outcomes from the study as well. We have been invited to submit an article to the “Tree Care Industry Magazine” for summer publication. The Tree Care Industry Association,, has also linked to the press release on the research at UNC. This will provide an opportunity for tree service workers across the country to learn from our research findings. Ultimately, we have plans to submit a manuscript to a peer-reviewed research journal.

Q: What kind of reactions did you receive from workers involved in the study? How about reactions at the winter tree care workshop? Did the information lead to any changes among employers?
TL: Most of the workers were shocked at how much noise they were exposed to on a single day. For instance, one of the highest readings suggested that a single worker received as much as 20 days worth of allowable noise exposure in one single workday. This makes the numbers more real for the workers. When I explained the different sound levels and how long they can be exposed before damage starts to occur, most of them couldn’t believe it.
The participants at the winter tree care workshop were extremely interested in the study results. Most of the attendees recognized that their equipment was “noisy,” just not how dangerous it truly is. There is also an interesting perception among workers in that the “nosiest” piece of equipment is the one they should be concerned about (e.g., chippers) and that other pieces of equipment that are quieter in comparison are of no concern. The workshop was able to highlight the message that most of their equipment emits harmful noise levels and that hearing protection is needed for all exposures, not just the “loudest” ones. The workshop attendees also spent lots of time discussing hearing protection options with Dr. Meinke at an exhibit table where earplugs were provided to attendees and different types of earmuffs were demonstrated, including electronic earmuffs that allow radio-activated speech communication between workers.
Sonie Harris, Au.D. (UNC clinic supervisor) and audiology graduate students also provided hearing testing in the UNC Mobile Audiology Clinic during the workshop. Over 75 persons took advantage of this opportunity which further reinforced the importance of protecting their hearing.

Q: How does the research apply to say a homeowner who’s using a chainsaw to do some pruning? At what point does noise from a chainsaw become unsafe?
TL: The research can apply to homeowners by making them aware that the noise levels of a chainsaw are dangerous and that it is better to take precautionary measures and protect their hearing even if they are only operating the chainsaw intermittently off and on. Through my research I found that chainsaws emit noise levels of between 86-112 dBA. The variability is dependent upon the size of the chainsaw, the operational mode and the proximity of the saw to the ear. For instance, if you bend over to saw a limb, you may be putting your ear closer to the engine and the ear will be exposed to a higher sound level. Occupational regulations and recommendations recognize that any sound over 85 dBA for extended periods of time may be hazardous to your hearing. OSHA (the Occupational Safety and Health Administration) also prohibits sound levels in excess of 115 dBA since hearing protection may not adequately protect hearing at these extreme levels. Using the guidelines offered by the National Institute for Occupational Safety and Health (NIOSH), exposure at 100 dBA is permitted for 15 minutes and is equivalent to an exposure of 8 hours duration at 85 dBA. In the case of the loudest chainsaws at 112 dBA, the allowable exposure time would be 56 seconds. Hardly enough time to do the work without ear protection. At high levels of exposure like these, the use of dual hearing protection (earplug plus an earmuff) is advised.
Homeowners are equally at risk if trimming their own trees, cutting firewood and chipping branches. Some homeowners rent chippers for some major projects. Homeowners that work a noisy job in another industry during the day may be at even greater risk when they add to their overall noise exposure level with off-the-job noise exposure in the evenings or weekends.

Q: How gratifying is to see your research being publicized and possibly leading to changes in practices?
TL: It is really rewarding to know that through my research people are being influenced in a positive way. In some indirect way, I may be increasing a person’s quality of life by preventing individuals from acquiring NIHL by making them aware of how to protect themselves from the dangerous levels of noise that they are exposed to daily at their job. Prevention is key.

Q: What’s next in line for the research?
TL: I am completing a clinical doctorate in audiology, so I will be focused on applying and strengthening my clinical skills while on externship during my last year in the program. I will not be directly involved in any additional research on the topic at this point in time, but hope that other students may become interested in the topic and consider extending the research. Ideally, we would obtain more data from the small, self-employed tree service workers and learn more about any potential barriers to the use of hearing protection among this group. I will certainly integrate this research experience into my clinical practice and would hope that dissemination of the findings will become widespread enough to see that employers are offering hearing loss prevention programs to their workers in the future. I’m sure my research advisor, Dr. Meinke, will engage in additional studies related to the prevention of noise-induced hearing loss as that is her primary research focus.
I will be planning on presenting my research outcomes at the National Hearing Conservation Association annual conference in February of 2011.
Currently I am completing my clinical externships working as an audiology intern at Alpine ENT (“All About Hearing” at both their Fort Collins and Loveland offices). Upon completing this externship in August 2010, I will be placed at Rocky Mountain ENT in Littleton to finish my clinical externships before graduating in May 2011 with my AuD. (Doctor of Audiology degree).
I would like to thank the employers and workers who participated in the study. They were very cooperative in terms of letting me onsite to make the measurements. I learned a lot about the practical aspects of making noise exposure measurements on workers and the value it can add to their workplace safety.

Highlights of the Research

- The research concluded that urban tree service workers are exposed to noise levels that exceed OSHA standards and NIOSH criteria and workers are at risk for occupational noise induced hearing loss (recommend protection at 85 dBA).
- 20 men ages 21-57 years from seven employers participated in the study last summer. Their length of service ranged from one month to 28 years.
- Research found that 95 percent of workers (19) worked in conditions that exceed either OSHA and/or NIOSH limits for on-the-job noise exposure.
- Using a noise dosimeter to measure exposure in working conditions, research showed that ear protection should be used when operating chainsaws, chippers, stump grinders, leaf blowers, water trucks, rotochoppers, tractors, brush/weed trimmers.
- Workers ranked chippers (measured at 112-119 dBA) as emitting the loudest noise. Noise exposures above 115 dBA are not permitted by OSHA. Efforts to control the noise source are needed by equipment manufacturers to reduce the hazard such equipment presents to the operators.
- Eighty percent of the workers routinely wore hearing protection (earplugs, earmuffs or combination earplug/earmuff). Recommendation to wear both earplugs and earmuffs when noise levels exceed 100 dBA (operating leaf blowers, chippers, chainsaws.) is advised.
- Three of the seven employers had components of hearing loss prevention programs, but only one had a comprehensive hearing conservation program as required by OSHA.A comprehensive hearing loss prevention program includes; noise measurement, noise control, hearing protection device fitting and use, worker training, annual hearing testing and the recordkeeping and effectiveness components of each of these components. Employers were most likely to provide earplugs/earmuffs to their workers but not oversee its use or fitting or provide the other necessary program components. It appears that many employers and employees may not be fully aware of the risk of noise-induced hearing loss in this industry and the best ways to prevent it. Many tree services are small, seasonal, self-employed entities that are not required to comply with OSHA. Voluntary hearing loss prevention programs are encouraged for these workers as well.