In a 2017 release the Centers for Disease Control (“CDC”) reported Noise Induced Hearing Loss (“NIHL”) is a significant health problem, affecting an estimated 20% of young adults aged 20-29 increasing to 25% among adults 50-59. Those numbers are growing every year. However, the National Institute of Occupational Safety and Health (“NIOSH”) states “NIHL is 100% preventable.” Not everyone who smokes gets lung cancer, and not everyone exposed to loud noise will have hearing loss. However, “once acquired, it is permanent and irreversible. It can result from a one-time exposure to a very loud sound, blast or impulse, or from listening to loud sounds over an extended period. NIHL can lead to communication difficulties, learning difficulties, pain (hyperacusis) or ringing in the ears (tinnitus), and distorted or muffled hearing.” This article explores what is a safe sound level for the public, and where can you find it?
1. Short Answer
If it seems loud it likely can be damaging to your ears. In order to protect your hearing the CDC, and countless other medical, engineering and public health officials, suggest everyone: (a) turn down the volume, (b) avoid, move away or limit exposure to loud sounds, and if that’s not possible, as a last resort, (c) use hearing “protection” devices that have limited effect.
Have you noticed we’ve stopped talking about preventing climate change? Now all we hear is how to “adapt” to it. Unfortunately, it seems we have given up on preventing NIHL. We are now expected to either lose our precious hearing, or stop participating in everyday society. Although some people need a little noise to ameliorate existing conditions, no one is injured by quiet and silence. It usually leads to less stress, increased concentration and perception. My Turn Up the Quiet TM initiative advocates these issues often can be addressed by simply turning the dial.
2. How Did We Get Here?
There are decades of research and seemingly conflicting recommendations from multiple sources that one must analyze and evaluate in light of current science in order to properly understand safe sound levels. (I apologize that to be thorough this “deep dive” will be lengthy, but we’ll have all the major aspects together in one article.)
As my readers know, I strongly believe individuals in America have the right to choose to risk their hearing, just as people have the right to smoke. That comes with some caveats. First, one person’s personal choice to does mean they have the right to risk the hearing of others. Second, the public has the right to be thoroughly advised of the risks in order to make an informed decision. Third, both work and public places are duty bound to provide safe alternatives.
a. Government Guidelines. NIOSH makes recommendations to OSHA for worker safety and states the “most effective way to prevent NIHL is to remove noise from the worker or remove the worker from noise.” In 1998, NIOSHestablished the “recommended exposure limit (“REL”) for occupational noise of 85 decibels dBA over an 8-hour time-weighted average. Exposures at or above this level are considered hazardous.”
However, NIOSH assumes 15% of the workers exposed to their “safe” limits will develop hearing loss. The World Health Organization (“WHO”) recommends an REL of no more than 80 dBA for 40 hours per week. Although workers are paid to take risks (if they are informed), and have the benefit of workers comp insurance, that doesn’t apply to the general public. NIOSH clearly states their limits are not “a recommendation for noise exposures outside of the workplace,” and recommends taking “precautions to protect your hearing by reducing the noise whenever sounds reach 85 dBA is a good health practice no matter where your ears are!” Nevertheless, the workplace guidelines are often misused as guidelines for the general public.
Furthermore, NIOSH falsely “assumes that the individual spends the other 16 hours in the day, as well as weekends, in quieter conditions. It does not account for noisy activities or hobbies outside the workplace, such as hunting, power tool use, listening to loud music with ear buds, or attending sporting events, movies and concerts. Some single, brief intense exposures [such as gun shots and rimshots] can cause immediate hearing loss.” In addition, the risk from combined exposure to continuous and impulsive noise, such guitars and drums, is synergistic and requires a correction factor further reducing REL.
So, what is a safe REL for the public? In 1974 the Environmental Protection Agency (“EPA”) stated a 24 hour environmental REL of 70 dBA over a lifetime will prevent measurable hearing loss. The EPA also notes background levels above 55 dBA outdoors and 45 dBA indoors can interfere with “spoken conversation and other activities such as sleeping, working and recreation.” Although the EPA states these safe limits are “to provide a basis for state and local governments’ judgments in setting standards,” the actual report also says “it does not constitute a standard, specification, or regulation.” It seems like the EPA was hedging its bets, and in 1982 abandoned public hearing safety when it shuttered its Office of Noise Abatement and Control.
Unfortunately for the public, that means there is no recognized federal standard to protect your hearing! Nevertheless, informed experts recommend following the EPA REL of 70 dBA whenever possible. That begs the question, where can you find safe places in today’s noisy world?
b. Sound Level Measurement is Complicated. Decibels can be measured at actual levels over the range of hearing (“dBZ,” sometimes referred to as “dB”) or with different weighting scales designed to simulate what the ear might hear. The most commonly used frequency weighting system, dBA, was designed for use with softer sounds, at whisper level around 40 dB, and underweights loud low-end bass frequencies by as much as 90%. The rarely used dBB weighting is designed for midlevel sounds, like a vacuum cleaner at around 70 dB. The dBC weighting is designed for loud sounds above 100dB, like those that occur at amplified events. In addition, there are time weightings of Slow (one second rise and decay, that filters out impulsive sounds and often used with 40 dBA soft sounds), Fast (125 microseconds, often used for 100 dBC loud sounds) and Impulse (40 microseconds, designed for accurate measurement of bells, beeps, gun shots, jackhammers, sirens, etc.). For concerts with impulsive sounds such a cymbals and drums, dBC Fast weighting is considered the closest representation of human hearing and recommended by WHO.
Many entertainment permits require measurements in both dBA Slow and dBC Fast weighting, where levels can exceed 120 dBA. Unfortunately, many concert venues, regulators, even some sound engineers and musicians, prefer to use dBA Slow weighting because it makes both loud sustained and impulsive sounds appear quieter, even though that increases the risks for workers, patrons and neighbors. Studies have found 30% of rock and over 50% of classical musicians have some degree of hearing loss, and similar levels of tinnitus. Many musicians and dancers want to “feel the noise” and develop hearing loss, then turn up the volume even louder, while other performers are afraid to ask to turn the music down.
A further complication is measurements often are not made at the source of the sound. For example, 120 dBA at 100ft is equivalent to 132 dBA at 25 feet, where injury can occur in less than 1 second. Precision sound measuring equipment records the actual sound plus all the various frequency and time weightings simultaneously, and should be measured at multiple locations for a clear understanding of the noise environment.
Therefore, although the public generally knows loud sounds can be risky, it is provided with conflicting information and has no idea how much risk they are exposed to every day. For example, there are noise activated warning signs for hospitals, schools, office and industry that are green for recommended safe levels up to 60 dB, yellow up to 75, orange up to 85 and red above 85. But one of the same manufacturers states “most of our customers are using sound meters to comply with noise limits,” and therefore “using our meters to help create more noise may seem unconventional.” Nevertheless, Larson Davis is “proud” to help “football teams use our products to make some noise.” Their meters “integrate seamlessly with scoreboards” to “improve the fan experience” by measuring the “extremely high level of noise.” They proudly proclaim “our meters measured the Kansas City Chiefs’ crowd generating 142.2 dB of noise,” when they “successfully took the title of loudest stadium.” What is the public to think when the same company that warns about noise over 60 dB then hypocritically encourages recklessly dangerous noise over 140 dB?
c. Hearing Protection. Will earplugs and earmuffs protect you? Not as much as you might think. Even though they have limited protection, “when engineering controls are not feasible for reducing noise exposures to safe levels” NIOSH, OSHA, WHO, and the CDC all agree hearing protection is necessary However, manufacturer claims are not regulated. NIOSH is highly critical of, and reports many problems with, earplugs and earmuffs. The industry has created a non-scientific rating standard, NRR (noise rating reduction), that vastly overstates protection (up to 2,000%) and is so flawed it’s not approved for use for any purpose by NIOSH, and recommends “the labeled NRR be derated by 70%” for earplugs that aren’t formable. I personally use 3M’s “professional earmuffs” when working in the yard. The box says it reduces “noise levels by 30 dB.” But on another panel they disclose that’s NRR, and the fine print inside the box states “3M makes no warranty as to the suitability of NRR as a measure of actual protection from any noise level… and may not be an accurate indicator of the protection attainable against impulsive noise… 3M recommends reducing the NRR by 50% for estimating the average amount of noise reduction provided.” In other words, the best you can expect in the real world is half the protection for certain non-impulse sounds. Some people use “double protection,” earplugs and earmuffs, but rather than adding the two NRR numbers together, you simply add five more decibels of protection to the device with the higher NRR. For example, using earplugs with an NRR 29 and earmuffs with NRR 27 would provide an NRR of approximately 34 dB. But then one needs to reduce the NRR by 50%, and the “estimated” actual protection for certain non-impulsive sounds is closer to 17 dB. Even using the NIOSH worker “safe” REL of 85 dBA, double protection is ineffective above 102 dBA. For the public using the EPA REL of 70dBA, double protection is ineffective above 87 dBA.
In addition, hearing protection is not beneficial in places where communication is required like stores or restaurants due to the “occlusion effect,” which causes your own voice to sound unusually loud. You tend to lower your voice, and then others have difficulty hearing you in the noisy environment. Communication is even more difficult when both parties are wearing hearing protectors, plus you can’t tell which direction sound is coming from or separate it from background noise (the “cocktail party effect”). Active Noise Cancelling (“ANC”) has issues too. ANC claims are also unregulated, and in the fine print you find it’s “more effective” at reducing “low-frequency sounds…and continuous or predictable sounds, than sudden or unpredictable ones.” In other words, they are helpful when you are on a plane, but not at a loud sporting event, nightclub or concert.
Finally, if you have tinnitus, hyperacusis or other sound sensitivities, the use of hearing protection is generally not advised. Earplugs deprive the auditory system of sound, and the ears try to compensate by making the quieter sounds louder, which may exacerbate the condition.
d. The Two Sides of Threshold Shift. Many people when first exposed to an unsafe sound perceive it as loud, and then after time do not perceive it as being so loud. This is called threshold shift. However, it doesn’t mean one’s ears have safely adapted and continued exposure can contribute to hearing loss, tinnitus, hyperacusis and other conditions. On the other hand, when exposed to safe quieter sounds and silence, threshold shift results in an increased sensitivity allowing one to fully enjoy the subtle complexity, nuance and beauty of natural sound.
e. So How Risky is It? Studies have shown that as many as 1 in 5 young people may already suffer from hearing damage, because of the ubiquitous and constant use of ear buds. WHO notes 50% of people aged 12-35 are at risk of hearing loss due to prolonged and excessive exposure to loud sounds, and recommends limiting ear bud use to 60 minutes a day. The FDA claims more than 30 million American adults report some degree of hearing loss, and Apple notes “1 in 3 people experience excessive noise on a regular basis.”
f. What about Hearing Aids? Hearing aids are vital for people with severe hearing loss. However, as the severity of hearing loss increases, the ability of hearing aids to help one hear better often decreases and surgery or cochlear implants may be necessary. If you have access to audiologists and otolaryngologists through insurance, you should take advantage of their expertise. They understand the complexity of hearing, know how to evaluate the severity of loss, how to prevent further injury, the range of technical options, and how to identify and treat the related the impact on communication, concentration, anxiety, depression, social isolation and loneliness.
I also support OTC hearing aids as providing cost effective options for informed consumers with mild to moderate hearing loss. But those waters are getting murky too. In September 2024, the FDA authorized Apple’s Air Pods Pro 2 as an OTC hearing aid only for adults. (I posted a separate blawg about it, and will summarize the issues here.) Apple is promoting Air Pods Pro 2 for an “all in one hearing health experience,” to also be used as a hearing aid after your hearing is damaged, and as a tool to for hearing “protection.” Apple says it’s suitable for use to listen, aid and protect “throughout the day.” Then the Apple fine print notes they are “not suitable for protection” against loud impulsive sounds or “sustained sounds above 110 dBA.” Recorded levels at music concerts reach 139 dB. Levels at sporting events can exceed 140 dB. Sounds from personal listening devices and loud music venues may reach 120 dB for hours on end. It seems Apple helps create the problem, then markets “solutions” filled with takebacks about the limited protection. That’s like putting asthma medicine in filter cigarettes.
g. Regulation to Protect the Public. Sound is supposed to be regulated with limitations on sound levels and/or permitted time periods. A recent blawg discussed regulations protecting people who live close to outdoor amphitheaters. Patrons are at an exponentially higher risk. Public safety requires a combination of properly drafted regulations, accurate records, independent oversight, accountability and due process. Although the EPA, state and local governments are charged with enforcement, for a number of reasons compliance is often underfunded and relegated to low priority with no monitoring equipment, no training and no one assigned to enforcement. One can’t count on government to provide a safe environment.
h. And the Band Played On. Based on the foregoing it’s no surprise the CDC states the general public is “largely aware of the hazard posed by high sound levels.” We are going from one noisy place to another without warning or adequate protection. Both government and businesses have failed to properly notify us that going to the sporting events, concerts, movies or even restaurants not only may, but will, cause permanent hearing injury for more than 25% of the population. The cumulative effect of regular exposure to “approved” levels of 105, 110, 115 and 125 dBA, with actual levels up to 140dBA, is a recipe for a society with increasingly severe, permanent and irreversible hearing impairment.
3. Conclusion
Where is it safe for the public? The reality is unless you want to live your entire life in a sound proofed bubble, or the middle of an empty field, you will be exposed to unsafe sound every day. The government, manufacturers, venues and businesses have no justification for these health dangers. Unfortunately, it seems the only motivating force for change in America is money damages. For example, in 2023 3M agreed to pay $6 billion to settle most of the 300,000 individual claims relating to overstated promises of protection for its Combat Arms earplugs. There will be additional class action lawsuits with huge damages, and only then will the fear of future liability bring safer sound levels.
For now, America…you’re on your own.
Copyright John Drinkwater 2024 All Rights Reserved Turn Up the Quietä
Disclaimer: This content is provided for general informational purposes only, and may not reflect the current law in all jurisdictions. No information contained in this post should be construed as legal advice nor is it intended to be a substitute for legal counsel on any subject matter. Readers should consult their own advisor for legal or other advice.