Occupational hearing loss
Occupational hearing loss (OHL) is hearing loss that occurs as a result of occupational hazards, such as excessive noise and ototoxic chemicals. Noise is a common workplace hazard, and recognized as the risk factor for noise-induced hearing loss and tinnitus but it is not the only risk factor that can result in a work-related hearing loss.[2] Also, noise-induced hearing loss can result from exposures that are not restricted to the occupational setting.[citation needed]
OHL is a prevalent occupational concern in various work environments worldwide. Many chemicals have not been tested for ototoxicity, so unknown threats may exist.
A 2016 study by NIOSH found that the
Personal protective equipment, administrative controls, and engineering controls can all work to reduce exposure to noise and chemicals, either by providing the worker with protection such as earplugs, or by reducing the noise or chemicals at the source or limiting the time or level of exposure.
Background
External videos | |
---|---|
A video hosted by the National Hearing Conservation Association about noise-exposed workers with hearing loss or tinnitus |
OHL is defined as any type of hearing loss, i.e. sensorineural, conductive, or mixed hearing loss, that occurs due to hazardous characteristics of a work environment.[11] The hearing loss can range in severity from mild to profound[11] and can be accompanied by tinnitus. Hazards of a work environment that can result in OHL include excessive noise, ototoxic chemicals, or physical trauma.[11] OHL caused by excessive exposure to noise is also known as noise-induced hearing loss (NIHL). Noise exposure combined with ototoxic chemical exposure can results in more damage to hearing. OHL caused by physical trauma may include foreign bodies in the ear, vibration, barotrauma, or head injury. OHL, as well as hearing loss in general, can cause negative secondary social and emotional effects that can impact quality of life.[12][13]
Within the
Causes
Noise exposure
Exposure to noise can cause vibrations able to cause permanent damage to the ear. Both the volume of the noise and the duration of exposure can influence the likelihood of damage. Sound is measured in units called decibels, which is a logarithmic scale of sound levels that corresponds to the level of loudness that an individual's ear would perceive. Because it is a logarithmic scale, even small incremental increases in decibels correlate to large increases in loudness, and an increase in the risk of hearing loss.[citation needed]
Sounds above 80 dB have the potential to cause permanent hearing loss. The intensity of sound is considered too great and hazardous if someone must yell in order to be heard.
NIOSH establishes recommended exposure limits (RELs) to protect workers against the health effects of exposure to hazardous substances and agents encountered in the workplace. These NIOSH limits are based on the best available science and practices. NIOSH established the REL for occupational noise exposures to be 85 decibels, A-weighted (dB[A]) as an 8-hour time-weighted average.[16] Occupational noise exposure at or above this level are considered hazardous. The REL is based on exposures at work 5 days per week and assumes that the individual spends the other 16 hours in the day, as well as weekends, in quieter conditions. NIOSH also specifies a maximum allowable daily noise dose, expressed in percentages. For example, a person continuously exposed to 85 dB(A) over an 8-hour work shift will reach 100% of their daily noise dose. This dose limit uses a 3-dB time-intensity tradeoff commonly referred to as the exchange rate or equal-energy rule: for every 3-dB increase in noise level, the allowable exposure time is reduced by half. For example, if the exposure level increases to 88 dB(A), workers should only be exposed for four hours. Alternatively, for every 3-dB decrease in noise level, the allowable exposure time is doubled, as shown in the table below.[citation needed]
OSHA's current permissible exposure limit (PEL) for workers is an average of 90 dB over an 8-hour work day. Unlike NIOSH, OSHA uses a 5-dB exchange rate, where an increase in 5-dB for a sound corresponds to the amount of time workers may be exposed to that particular source of sound being halved. For example, workers cannot be exposed to a sound level of 95 dB for more than 4 hours per day, or to sounds at 100 dB for more than 2 hours per day. Employers who expose workers to 85 dB or more for 8 hour shifts are required to provide hearing exams and protection, monitor noise levels, and provide training.[citation needed]
Time to reach 100% noise dose | Exposure level per NIOSH REL | Exposure level per OSHA PEL |
---|---|---|
8 hours | 85 dBA | 90 dBA |
4 hours | 88 dBA | 95 dBA |
2 hours | 91 dBA | 100 dBA |
1 hours | 94 dBA | 105 dBA |
30 minutes | 97 dBA | 110 dBA |
15 minutes | 100 dBA | 115 dBA |
Sound level meters and dosimeters are two types of devices that are used to measure sound levels in the workplace. Dosimeters are typically worn by the employee to measure their own personal sound exposure. Other sound level meters can be used to double check dosimeter measurements, or used when dosimeters cannot be worn by the employees. They can also be used to evaluate engineering controls aimed at reducing noise levels.[citation needed]
Some recent studies suggest that some smartphone applications may be able to measure noise as precisely as a Type 2 SLM.[17][18] Although most smartphone sound measurement apps are not accurate enough to be used for legally required measurements, the NIOSH Sound Level Meter app met the requirements of IEC 61672/ANSI S1.4 Sound Level Meter Standards (Electroacoustics - Sound Level Meters - Part 3: Periodic Tests).[19]
Ototoxic chemical exposure
Chemically induced hearing loss (CIHL) is a potential result of occupational exposures. Certain chemical compounds may have
Both noise and chemical exposures are common in many industries, and can both contribute to hearing loss simultaneously.[23] Damage may be more likely or more severe if both are present, in particular if noise is impulsive.[24][25] Industries in which combinations of exposures may exist include construction, fiberglass, metal manufacturing, and many more.[22]
It is estimated that over 22 million workers are exposed to dangerous noise levels, and 10 million are exposed to solvents that could potentially cause hearing loss every year, with an unknown number exposed to other ototoxic chemicals.[21] A 2018 informational bulletin by the US Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) introduces the issue, provides examples of ototoxic chemicals, lists the industries and occupations at risk and provides prevention information.[2]
Prevention
OHL is preventable, but currently the interventions to prevent it involve many components. Stricter legislation might reduce noise levels in the workplace.
Hierarchy of controls
The
- Elimination: complete removal of the hazard
- Substitution: replacement that offers a smaller risk
- Engineering controls: physical changes to reduce exposure
- Administrative controls: changes in work procedures or training
- Personal protective equipment (PPE): individual equipment to reduce exposure, e.g. earplugs [27][28]
Engineering controls
Engineering controls is the next highest in the hierarchy of risk reduction methods when elimination and substitution of the hazard are not possible. These types of controls typically involve making changes in equipment or other changes to minimize the level of noise that reaches a worker's ear. They may also involve measures such as barriers between the worker and the source of the noise, mufflers, regular maintenance of the machinery, or substituting quieter equipment.[29][30]
The OSHA Technical Manual (OTM) on noise provides technical information about workplace hazards and controls to OSHA's Compliance Safety and Health Officers (CSHOs).[31] The content of the OTM is based on currently available research publications, OSHA standards, and consensus standards. The OTM is available to the public for use by other health and safety professionals, employers, and anyone involved in developing or implementing an effective workplace safety and health program.
Administrative controls
Administrative control, behind engineering control, is the next best form of prevention of noise exposure.[29] They can either reduce the exposure to noise, or reduce the decibel level of the noise itself. Limiting the amount of time a worker is allowed to be around an unsafe level of noise exposure, and creating procedures for operation of equipment that could produce harmful levels of noise are both examples of administrative controls.[30]
Personal protection
Elimination or reduction of the source of noise or chemical exposure is ideal, but when that is not possible or adequate, wearing personal protective equipment (PPE) such as earplugs or earmuffs can help reduce the risk of hearing loss due to noise exposure. PPE should be a last resort and not be used in substitution for engineering or administrative controls. It is important that workers are properly trained on the use of PPE to ensure proper protection.[30] A personal attenuation rating can be objectively measured through a hearing protection fit-testing system.[citation needed]
Other initiatives
In addition to the hierarchy of controls, other programs have been created to promote the prevention of hearing loss in the workplace. For example, the
History
Occupational hearing loss is a very present industrial issue that has been noticed since the Industrial Revolution.[34] As industrial society continues to grow, this issue is becoming increasingly detrimental due to the exposure of chemicals and physical objects. Millions of employees have been affected by occupational hearing loss, especially in industry.[35] Industrialized countries see most of these damages as they result in both economic and living problems.
Within the United States of America alone, 10 of the 28 million people that have experienced hearing loss related to noise exposure. Rarely do workers express concerns or complaints regarding Occupational hearing loss. In order to gather relevant information, workers who have experienced loud work environments are questioned regarding their hearing abilities during everyday activities. When analyzing OHP, it is necessary to consider family history, hobbies, recreational activities, and how they could play a role in a person's hearing loss. In order to test hearing loss, audiometers are used to and are adjusted to American National Standards Institute (ANSI) regulations. The Occupation and Safety Health Association (OSHA) of the United States of America requires a program that conserves hearing when noise levels are greater than 85 dB.[citation needed]
See also
- Noise-induced hearing loss
- Hearing conservation programs
- Hearing protection fit-testing
- Hearing loss
- Tinnitus
- Ototoxicity
- Noise
- Safe-in-Sound Excellence in Hearing Loss Prevention Award
- Safe listening
- World Hearing Day
- World Report on Hearing, World Health Organization, 2021.
- Health problems of musicians
References
- PMID 25690583.
- S2CID 208626669.
- PMID 26042421.
- S2CID 256740944.
- ^ Johnson AC, Morata TC (2010). "Occupational exposure to chemicals and hearing impairment. The Nordic Expert Group for Criteria Documentation of Health Risks from Chemicals" (PDF). Arbete och Hälsa. 44 (4): 177.
- .
- PMID 21783525.
- PMID 27101435.
- PMID 31795665.
- ^ S2CID 220284470.
- ^ PMID 21258593.
- PMID 14570962.
- S2CID 14433959.
- ^ NIOSH (Mar 22, 2018). "Noise and Hearing Loss Prevention". Retrieved Jul 10, 2018.
- ^ a b "CDC - Facts and Statistics: Noise - NIOSH Workplace Safety & Health". www.cdc.gov. Retrieved 2016-03-30.
- ^ NIOSH (1998). "Criteria for a Recommended Standard - Occupational Noise Exposure" (PDF). Retrieved Jul 9, 2018.
- PMID 25236152.
- PMID 27794313.
- S2CID 116822722.
- ^ EU-OSHA, European Agency for Safety and Health at Work (2009). "Combined exposure to noise and ototoxic substances". Combined exposure to noise and ototoxic substances. EU OSHA. Retrieved May 3, 2016.
- ^ a b "CDC - NIOSH Topic: Occupational Hearing Loss (OHL) Surveillance". www.cdc.gov. Retrieved 2016-03-28.
- ^ a b "Ototoxic chemicals - chemicals that result in hearing loss". Department of Commerce Western Australia. 2014-01-08. Retrieved 2016-03-28.
- PMID 23507352.
- PMID 29604694.
- PMID 25689156.
- ^ PMID 28685503.
- ^ "Hierarchy of Controls". SA Unions. Archived from the original on June 23, 2005. Retrieved July 13, 2016.
- ^ "Hierarchy of Controls". Centers for Disease Control and Prevention. Retrieved July 13, 2016.
- ^ a b "NIOSH - Engineering Noise Control - Workplace Safety and Health Topic". www.cdc.gov. Retrieved 2016-03-30.
- ^ a b c "Noise controls (Engineering, Administrative, PPE) | Mining Safety & Health Resource Center". miningsh.arizona.edu. Retrieved 2016-03-30.
- ^ OSHA (Aug 15, 2013). "OSHA Technical Manual - Noise". Retrieved Jul 10, 2018.
- ^ "Buy Quiet". Centers for Disease Control and Prevention. Retrieved July 13, 2016.
- ^ "Excellence in Hearing Loss Prevention Award". Safe-in-Sound. Retrieved July 13, 2016.
- ISBN 978-0-8247-8814-8.
- PMID 11500698.
External links
- Noise-Induced Hearing Loss from the National Institutes of Health
- Dangerous Decibels Includes general information and a "virtual exhibit" as well as resources for teachers.
- Noise and Hearing Loss Prevention Topic Page by the National Institute for Occupational Safety and Health.
- Power Tools Sound Pressure and Vibrations Database by the National Institute for Occupational Safety and Health.
- New York City construction noise control products and vendor guidance sheet
- Online Audiometric Test with stimuli up to 80 dBHL. Confirm your hearing status and track if it changes over time.
- An online audiometric test featuring equal loudness curves
- www.cochlea.org/en/noise - animation of damage of hairs, harmful intensities graph
- www.cochlea.eu/en/hair-cells - illustrations and images of hair cells