here is a proven relationship between exposure to solvents and hearing loss. Exposures to organic compounds such as Styrene, Toluene and other aromatic hydrocarbons have been linked to reduced hearing capabilities in humans, caused by the ototoxic effects of these substances. They cause the neurological sensory systems to decrease in their capabilities following long-term exposure resulting in sensorineural hearing loss.
The effects of exposure are often related to the central nervous system where those effects can cause symptoms such as tiredness, drowsiness, nausea, increased stress levels, depression, anxiety and in some cases, fainting and even death. However, the ototoxicity of these types of chemical agents is often overlooked and the relationship between noise exposure and chemical exposure holds some significance.
Often individuals who work in high noise environments can be undertaking work which involves the use of chemical agents that are organic substances. Paint sprayers, for example, are often exposed to higher levels of solvent-based substances and rely heavily on engineering controls such as spray booths. Within these spray booths, noise levels can reach heights greater than the exposure limit value of 87dB(A). These individuals are at significant risk of experiencing hearing loss and ototoxic effects if exposures are not adequately managed.
Research has been conducted on industrial printer operatives and reinforced fibre-glass plastic boat manufacturers whereby a significant relationship between exposures to toluene and styrene was suspected of causing increased hearing loss percentages. The loss of hearing may have been caused solely by exposure to organic chemicals without being exposed to high noise levels, although it is expected that a negative effect on hearing may occur synergistically.
Staggeringly, 49% of workers who were exposed to a mixture of organic solvents including Toluene, Ethyl Acetate and Ethanol in the printworks showed clear signs of hearing loss. It was estimated that the workers' odds ratio estimated hearing loss 1.76 times greater for each gram of hippuric acid per gram of creatinine, the biological marker for Toluene in the body.
Moving forward, businesses may start to consider the ototoxicity of organic substances and include these in their risk assessments relating to both chemical and noise exposures. In an attempt to raise a greater level of awareness around this type of neurotoxic effect caused by organic substances, our business has been delivering awareness training around the subject.