Tag Archive: National Institute for Occupational Safety and Health

Hearing Loss Is Growing

From the book The Human Body and Health Revised by Alvin Davison, 1908 / Public Domain

And Experts Say Earphones Are Part Of The Problem.

Mack interviews audiologist Michele Abrams who spoke about limiting exposure to damaging sound:

When we think about decibel levels, when we think of loudness levels, it’s really incremental.  It’s a logarithmic scale. It’s not a linear scale. So we know that 85 db is that critical level. Eighty-five db, eight hours a day, that’s your maximum. If it’s 90 db — five db greater — you have to cut your time in half.

While generally informative, Abrams’ comment unfortunately identifies 85 db, eight hours a day as the “critical level.”  But this noise exposure level is too high.  It was developed solely as an occupational noise exposure standard and should never be applied to the general public, certainly not to children.  As Dr. Daniel Fink, a noted noise activist, wrote in, “What Is A Safe Noise Level For The Public?”:

In the absence of a federal standard, an occupational standard meant to prevent hearing loss appears to have become the de facto safe level for all public noise exposures. This is demonstrated by the use of 85 decibels as a safe sound level by hearing health professionals and their organizations, in media reports, and in publications, most often without time limits; by its use as a volume limit for children’s headphones marketed to prevent hearing loss, again without exposure times; and by general acceptance of higher indoor and outdoor noise levels in the United States.

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Eighty-five decibels is not a safe noise exposure level for the public. In 1972, the National Institute for Occupational Safety and Health developed an 85 A-weighted decibel recommended exposure level to reduce the risk of hearing loss from occupational noise exposure. … Even with strict time limits, this standard does not protect all workers from hearing loss.

So what is a safe noise level for the public?  Dr. Fink states:

In 1974 the Environmental Protection Agency’s (EPA’s) Office of Noise Abatement and Control (ONAC) adjusted the National Institute for Occupational Safety and Health recommendation for additional exposure time: 24 instead of 8 hours daily and 365 instead of 240 days annually.  The EPA calculated the safe noise level for the public to prevent hearing loss to be a 70-decibel time-weighted average for a 24-hour period… The EPA did not adjust for lifetime noise exposure, now almost 80 years versus 40 work-years, so the real average safe noise level to prevent hearing loss is probably lower.

One thing is clear, allowing children to use earbuds or headphones without limiting volume and time exposure is a recipe for hearing loss.  Since the federal government has abdicated its authority to regulate noise, and manufacturers are unlikely to design products that limit the user’s ability to deliver as many decibels as he or she wants, parents must step in to protect their children’s hearing.  Here’s something that will help: Don’t allow your children to wear earbuds and headphones.  Tell them that if they want to listen to music they must play it through a speaker.  While this may be unpopular, know that you will be giving your children an important gift–the ability to listen to and enjoy music throughout their lifetimes.



Thinking about downloading a sound measurement app?

Read this National Institute for Occupational Safety and Health (NIOSH) review first:  So How Accurate Are These Smartphone Sound Measurement Apps?

Scroll to the end of the blog post for a November 2016 update to NIOSH’s initial 2013 study.

Headphones marketed as safe for children aren’t!


By Daniel Fink, M.D.

A new analysis on “the best kids’ headphones” by The Wirecutter, a product recommendations website owned by The New York Times, as reported in the New York Times science section, found that headphones marketed as “safe” for children’s hearing were louder than advertised. The Times’ article did not adequately reflect the extensive and thoughtful analysis by The Wirecutter’s reviewers, Lauren Dragan and Brent Butterworth. Their review deserves to be read (and reread) in its entirety, as it is without doubt the most complete and scientifically sound review about any noise topic that I have seen in the popular media.

The Wirecutter review mentions that two problems with headphones marketed as “safe for children”: (1) that the headphones are louder than they claim to be, and (2) that manufacturers are using an industrial-strength occupational noise exposure level as a safe noise level for children. The review doesn’t emphasize the latter point enough.

I discuss the origin of the 85 decibel noise exposure standard in detail in an editorial in the January 2017 issue of The American Journal of Public Health. The 85 decibel volume level at issue was developed by the National Institute for Occupational Safety and Health (NIOSH) to protect workers’ hearing. It comes with strict time limits–an 8-hour day, 240 days a year, for a 40-year work career–and even then does not protect all workers from hearing loss. NIOSH discussed the difference between an occupational noise standard and a safe noise level for the public earlier this year in a blog post titled, “Understanding Noise Exposure Limits: Occupational vs. General Environmental Noise.” The NIOSH post makes it very clear that 85 decibels is not a safe noise level for the public, and it certainly is not safe for toddlers or children who may be listening to music or watching videos for more than 7 hours a day, every day. In addition, children, and especially teens, are exposed to other loud noise sources–action movies, sports event, etc.–so their total noise dose likely approaches dangerous levels.

Children’s ears may be more sensitive to noise than adult ears. First, there is no doubt that an 85 decibel headphone speaker is closer to a child’s eardrum because the external auditory canal is shorter in children than adults. (Noise follows the inverse square law, so the closer a noise source is to the ear the louder it is.) Second, it’s unlikely that children will limit their listening to just 240 days a year, on average they will live for almost 80 years, and in the course of their lifetimes they will undoubtedly be exposed to more noise, in gyms, parties, rock concerts, sports events, and the like. A child’s delicate ears have to last her a whole lifetime.

Studies of auditory acuity in so-called primitive populations show that significant hearing loss in old age is not inevitable. These studies are not available online, so I can’t provide links, but the classic studies were done in the 1960’s by Rosen and colleagues in the Mabaan population in the Sudan, and by Dickson and colleagues in the Kalahari Bushmen. Rosen found that the Mabaan could carry on a conversation at normal speech volumes while facing away from each other at a distance of 100 yards. Dickson wrote that the Bushmen could hear an airplane 70 miles away. As noted in The Wirecutter review, acute hearing was a matter of life or death for our primitive ancestors, either to find food or to avoid being a predator’s meal. The Rosen and Dickson studies suggest that hearing loss so commonly seen in the U.S. is likely not part of normal part of normal physiological aging, but rather is noise-induced hearing loss–i.e., the result of a lifetime’s exposure to excessive noise. If one starts listening to 85 decibel sound at age 3, hearing loss and hearing aids may be inevitable–and at an earlier age than in the past.

What can be done to protect children’s hearing from dangerous consumer products marketed to them? The federal agencies charged with protecting the public should do their jobs. The Federal Trade Commission should take enforcement action on the grounds of false advertising against vendors claiming that headphones with the 85 decibel volume limit are safe for children. They may be safer than headphones without a volume limit, but they are by no means safe, especially without recommendations for time limits on use. The Consumer Product Safety Commission should require warning labels on headphones, earbuds, and personal music players, stating “LOUD MUSIC CAUSES DEAFNESS!” The pediatric community should do more to educate parents about the dangers of noise for children. And parents must step up and demand truly safe products for their children or deny their children access to products that will destroy their hearing.

Dr. Fink is a leading noise activist based in the Los Angeles area.  He serves on the board of the American Tinnitus Association, is the interim chair of Quiet Communities’s Health Advisory Council, and the founding chair of The Quiet Coalition, an organization of science, health, and legal professionals concerned about the impacts of noise on health, environment, learning, productivity, and quality of life in America.

Want a side of peace and quiet with your meal?

You are not alone: Diners want noise off the menu.

NOTE: The statement in the article that “[t]he Centers for Disease Control and Prevention recommends less than eight hours of sustained exposure to noise louder than 85 decibels,” is wrong in its implied scope.  In February 2016, the National Institute for Occupational Safety and Health (NIOSH) posted an article on its Science Blog that stated that the 85 dBA noise exposure limit was intended only as a limit for occupational noise exposure and not as a safe noise exposure limit for the public at large.  See, NIOSH Science Blog clarifies difference between occupational and general noise exposure limits.  According to Daniel Fink, M.D., a leading noise activist, the only evidence-based safe noise exposure level for the public was calculated by the Environmental Protection Agency to be 70 dB (unweighted) average noise exposure for a 24 hour period.  See, Information on Levels of Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of Safety.

NIOSH Science Blog clarifies difference between occupational and general noise exposure limits

Many people are confused about what is a safe noise limit for the general public because the only noise limit the public may have heard about is the 85 decibel recommended exposure limit (REL) that National Institute for Occupational Safety and Health (NIOSH) established for occupational noise exposures.  Fortunately, the NIOSH Science Blog has just posted an informative piece* that discusses acceptable RELS for both, titled: Understanding Noise Exposure Limits: Occupational vs. General Environmental Noise.

The authors state that in 1998, NIOSH established the REL for occupational noise exposure to be 85 decibels based on an 8-hour shift for a 5-day work week, adding that the REL “assumes that the individual spends the other 16 hours in the day, as well as weekends, in quieter conditions,” and cautioning that “the NIOSH REL is not a recommendation for noise exposures outside of the workplace in the general environment.”  The difference between the occupational and general environmental noise exposures is that:

The NIOSH REL is not meant to be used to protect against general environmental or recreational noise; it does not account for noisy activities or hobbies outside the workplace (such as hunting, power tool use, listening to music with ear buds, playing music, or attending sporting events, movies and concerts) which may increase the overall risk for hearing loss.

The authors point out that a 1974 Environmental Protection Agency (EPA) report recommended 70 decibels over a 24-hour average exposure limit for general environmental noise (while noting the EPA’s caution that its recommendation was not a standard, specification, or regulation).  This recommendation was determined in a similar manner as the NIOSH REL, but it’s focus was on general environmental noise and not the workplace.  As the EPA report states, their recommendation “was chosen to protect 96% of the general population from developing hearing loss as well as to protect ‘public health and welfare.’”

The authors note that both limits “are based on the same scientific evidence and the equal-energy rule,” but “are designed to protect against different problems.”  As a result, the limit values differ because “the EPA limit was averaged over 24 hours with no rest period while the NIOSH limit is averaged for just 8 hours and includes a rest period between exposures,” and the EPA limit includes an allowance “to protect against exposures for 365 days a year versus the NIOSH REL’s calculation that aims to protect against work place exposures for 250 working days a year.”   The authors add that “the EPA limit did not consider cost or feasibility of implementation as the Occupational Safety and Health Administration (OSHA), in accepting a NIOSH REL as the basis for a mandatory standard, [was] required to do under the Occupational Safety and Health Act of 1970.”

Long and short, the authors conclude that the 85 decibel REL is a work standard that neither mandates nor recommends decibel limits for the general public.  Rather, it is the EPA’s recommendation of 70 decibels that provides the appropriate exposure limits for the public with regard to general environmental noise.

*The post was prepared by NIOSH engineer, Chuck Kardous, MS, PE; NIOSH audiologist, Christa L. Themann, MA; NIOSH research audiologist Thais C. Morata, Ph.D., who is also the Coordinator of the NORA Manufacturing Sector Council; and W. Gregory Lotz, Ph.D, Captain, US Public Health Service, Division Director of the Division of Applied Research and Technology (DART), and the manager of the NORA Manufacturing Sector Council.