Background
Organic solvents are a chemical class of compounds that are used routinely in commercial industries. They share a common structure (at least 1 carbon atom and 1 hydrogen atom), low molecular weight, lipophilicity, and volatility, and they exist in liquid form at room temperature. They may be grouped further into aliphatic-chain compounds, such as n -hexane, and as aromatic compounds with a 6-carbon ring, such as benzene or xylene. Aliphatics and aromatics may contain a substituted halogen element and may be referred to as halogenated hydrocarbons, such as perchloroethylene (PCE or PER), trichloroethylene (TCE), and carbon tetrachloride. Alcohols, ketones, glycols, esters, ethers, aldehydes, and pyridines are substitutions for a hydrogen group. Organic solvents are useful because they can dissolve oils, fats, resins, rubber, and plastics.
Organic solvents arose in the latter half of the 19th century from the coal-tar industry. Their application grew to be wide and diverse in both developed and developing countries. The introduction of chlorinated solvents in the 1920s led to reports of toxicity. Although solvents number in the thousands, only a few have been tested for neurotoxicity.
Workers in industries that use these agents may have occupational exposure, whereas other individuals may have environmental exposures if they live near industrial installations and/or have contact with contaminated water, soil, air, or food. Drinking water, shower water, ambient air, indoor air, and food, among other sources, are common routes of exposure to environmental toxins.
Inhalation, ingestion, and dermal absorption are also important mechanisms of toxic exposure.
Exposures often involve mixtures of solvents. Some of these incidents may occur deliberately when an individual recreationally inhales paints, glues, and other products; these exposures are described in more detail in the Medscape Reference article Inhalants.
The Occupational Safety and Health Administration (OSHA) regulates worker exposure. The National Institute for Occupational Safety and Health (NIOSH) and the American Congress of Governmental Industrial Hygienists (ACGIH) also publish standards for use in occupational settings in the United States.