Most construction workers don’t know that exposure to loud, jarring noises isn’t the only way to damage their hearing. Exposure to ototoxic chemicals like solvents and heavy metals through inhalation, skin absorption, or ingestion can also lead to auditory damage. Once in the bloodstream, they invade the auditory pathway and cause damage, resulting in tinnitus and hearing loss. 

Quick look

• Ototoxic chemicals like arsenic and butanol damage the auditory nerves and structures of the inner ear
• Chronic exposure to chemicals can cause permanent damage to hearing or hearing-related issues like tinnitus
• Some research shows a link between marijuana use and tinnitus
• Job-related environmental factors and lifestyle choices contribute to hearing loss

What are ototoxic chemicals?

When inhaled, ingested, or absorbed through the skin, ototoxic chemicals damage the inner ear and auditory nerves, which can lead to tinnitus (a constant ringing, clanging, or hissing in the ears) and hearing loss. 

There are more than 100 potentially ototoxic chemicals, but the three main types include:

• Solvents like butanol, carbon disulfide, and ethanol
• Heavy metals like arsenic, lead, and manganese
• Asphyxiants like acrylonitrile, carbon monoxide, and hydrogen cyanide

Some medications, such as quinine and salicylic acids (including aspirin), can also be ototoxic substances, as is tobacco smoke. There’s no clear answer about marijuana smoke, but some research has linked it to tinnitus.

Generally, ototoxic substances are absorbed through the skin, but inhalation and ingestion can also occur. Because these substances adversely affect hearing, they can also alter a person’s sense of balance.

Impact of ototoxic chemicals on hearing

There are several ways ototoxicity can damage a worker’s hearing. These toxic substances themselves are known to cause certain kinds of permanent damage to the auditory system. Still, their damaging effects can be compounded when the worker also labors in an environment with constant loud noises. 

Some of the most common auditory effects of chemical exposure include:

• Tinnitus: A condition characterized by constant ringing, buzzing, or other sounds without an external source (other people can’t hear it)
• High-frequency hearing loss: The loss of ability to hear sounds in higher pitches
• Sensorineural hearing loss: Permanent hearing impairment due to damage of hair cells within the inner ear, the vestibulocochlear nerve, or the brain’s central processing centers
• Cochlear damage: Ototoxic chemicals can damage delicate structures of the inner eat, especially the cochlea 

Marijuana use and tinnitus

Some research has found a link between marijuana smoke and hearing issues, suggesting that it may be an ototoxic substance. And because marijuana use is high in the construction industry, proper education of construction workers is critical.

While about 10–25% of American adults sometimes experience tinnitus, some experts suggest that up to 10% have chronic tinnitus.

Protecting your hearing from the assaults of loud noises should be a given, but curbing smoking of any kind is another way to avoid auditory damage. 

Job-related and lifestyle risk factors

Exposure to ototoxic substances is common in many industries, including manufacturing, construction, mining, agriculture, and the utility sector. But workers in the printing, firefighting, and painting trades are the most heavily affected by exposure. 

Workers exposed to a combination of ototoxic substances, such as solvent fumes and exhaust from a machine or vehicle, or exposed to a combination of the ototoxic substance and loud noises, are at an increased risk of hearing loss. These environmental irritants affect hearing, and the effect is compounded when more than one irritant is present simultaneously.

Work activities that commonly combine noise and ototoxic substances include:

• Painting
• Printing
• Boat building
• Construction
• Furniture making
• Fueling vehicles and aircraft
• Manufacturing
• Degreasing
• Firefighting
• Firing weapons

Avoiding exposure to loud noises and ototoxic chemicals can help limit auditory damage, but that may be easier said than done in some industries. Proper personal protective equipment (PPE) and safety procedures become imperative in that case. For example, painters who work around solvents can reduce their risk by using proper ventilation, being diligent about personal hygiene at work, wearing appropriate PPE like gloves, masks, and hearing protection, and avoiding smoking (and second-hand smoke). 

Reducing harmful chemical exposure

Reducing chemical exposure isn’t always as easy as avoiding it altogether. Ototoxic chemicals are a big part of some industries, but workers can educate themselves on minimizing risk. 

Some of the easiest ways to limit chemical exposure include:

• Learn about what chemicals you’re dealing with
• Lower noise volumes or create mufflers
• Use proper ventilation 
• Substitute for less harmful chemicals whenever possible 
• Have your hearing checked regularly

Workers regularly exposed to ototoxic substances should, when possible:

• Reduce noise exposure to 80 dB or below
• Undergo a hearing test at least annually
• Be aware of ototoxic substances on their job site 
• Use appropriate PPE

Substituting a non-ototoxic substance for a harmful one is recommended for workers who regularly come into close contact with such chemicals. Isolating harmful fumes through an exhaust pipe or proper ventilation is also recommended. Workers should always use personal protective equipment to prevent skin and respiratory absorption.

Drugs/foods that can worsen hearing loss

Noise and chemicals are two biggies that contribute to hearing loss, but drugs and certain foods can, too—and many of them are things construction workers commonly consume. While some appear as seemingly benign foods, like coffee and beer, they can worsen hearing loss if it’s already begun. 

These foods, chemicals, and drugs all affect the auditory pathways, so it’s important to be cognizant of what you’re putting in your body, especially if you’re already dealing with hearing impairment of any degree. 

If you struggle with hearing, here are some consumables to avoid or limit:

• Alcohol: Damages hair cells in the ear that translate sound into nerve impulses for hearing, leading to permanent hearing loss
• Caffeine: Caffeine can cause temporary hearing loss or worsen existing hearing loss
• Nicotine: Nicotine can cause tinnitus, dizziness, and vertigo by changing or damaging cochlear hair cells, reducing oxygen circulation, and altering blood supply
• Opioids: Codeine, heroin, hydrocodone, morphine, and other opioids may impair auditory neuromodulation and cause hearing loss

Symptoms of ototoxicity

Ototoxic chemicals can damage the structures of the inner ear, leading to hearing and balance problems. Some problems, like tinnitus, can develop slowly and take years to notice, while others are more noticeable and problematic. 

Symptoms of ototoxicity can vary among individuals. Damage to the hearing organs can range from mild to severe hearing loss and may include tinnitus. If the organs controlling balance are damaged, symptoms can range from dizziness and nausea to imbalance and blurry vision. These symptoms may be temporary or permanent.

The most common symptoms of ototoxicity include:

• Hearing loss: This can be mild or severe, or even total hearing loss. It can be bilateral, affecting both ears and may go unnoticed until it affects a person’s ability to understand speech.
• Tinnitus: Also known as ringing in the ears, this is usually the first sign of ototoxicity.
• Balance problems: Can range from mild to severe and may include feeling dizzy or lightheaded, unsteady, or having trouble walking.
• Other symptoms: These may include a feeling of fullness in the ear, headache, and blurry vision (oscillopsia), which is when your vision bounces or blurs when you move your head.

Keep hearing safe from ototoxins 

To prevent ototoxic chemical-related hearing damage, use a mix of occupational safety measures, such as PPE, and frequent monitoring of hearing health. An audiometric test, also known as a hearing test, measures the ability to hear sounds and can help determine the cause of hearing loss. Workers should be tested at least annually, if not twice a year.

Here are six ways to protect yourself from hearing loss:

1. Use Personal Protective Equipment (PPE): Wear PPE ear protection, such as earmuffs or earplugs, to lower exposure to loud noises, and use chemical-resistant gloves to reduce exposure to ototoxic substances.
2. Control noise: Reduce noise levels through soundproofing.
3. Install ventilating systems: Ensure proper ventilation where ototoxic chemicals are present to disperse airborne chemicals and lower inhalation.
4. Practice good hygiene: Employers must promote good hygiene, like regular handwashing, to lower contact with ototoxic substances. Workers should avoid touching their faces and mouths while they are working.
5. Get your hearing tested regularly: Workers exposed to ototoxic substances should have regular audiometric testing to help detect changes in hearing early.
6. Enroll in safety training: Workers should be trained on the hazards of ototoxic substances to educate them on where exposure happens and how to reduce their risk.

Don’t fault yourself, protect yourself

If you’ve developed work-related hearing issues, it’s easy to blame yourself. But kicking yourself over something that’s already happened is counterproductive—focus on what you can do to prevent further damage to your hearing.

Working in the skilled trades can be a tough job that comes with its own set of risks, but protecting yourself from any risk is about educating yourself on where they are and what you can do to prevent them and protect your health. 

Due to the nature of many occupations, hearing damage happens on the job. Orchestral musicians, as do the farmers who work around heavy machinery, develop hearing loss due to the nature of their work. Put simply, protecting your hearing comes down to knowing the risks and mitigating them through education, proper PPE, and regular hearing tests.