Simultaneous exposure to physical and chemical hazards is common in the general environment. Chemical agents are present in air, water, food, and soil, and they contribute to many chronic diseases. However, most of the research studies focus on toxic effects resulting from exposures in the occupational environment, and therefore, this article will focus on this issue. In the case of hearing damage, a major concern arises about the deteriorating effects of chemical substances such as organic solvents, heavy metals, and asphyxiants, when they are acting alone or in combination with noise. Organic solvents like xylenes, toluene, styrene, trichloroethylene, and n-hexane and their mixtures are routinely used in industries, and they have detrimental effects both on peripheral and central parts of the auditory pathway as well as on vestibular system (balance). Some of these chemicals have been shown to be ototoxic even within recommended exposure limits. Commonly found combinations of chemicals and noise in the industry can induce exacerbation of the auditory impairment as compared to noise effects alone. Heavy metals are natural constituents of the earth's crust, but they are also extensively used in the industry. Commonly encountered heavy metals that could be ototoxic are lead, mercury, arsenic, and cadmium. Asphyxiants that promote development of hearing loss are carbon monoxide and hydrogen cyanide; they bind hemoglobin heme, thereby preventing oxygen transportation. Awareness should be raised among occupational physicians and decision makers that for exposures to some chemicals alone or in combination with noise, the current limits and hearing conservation programs might be inadequate. © 2011 Elsevier B.V. All rights reserved.