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Organic solvents are often the most hazardous chemicals in the work place. Solvents such as ether, alcohols, and toluene, for example, are highly volatile or flammable. Chlorinated solvents such as chloroform are nonflammable, but when exposed to heat or flame, may produce carbon monoxide, chlorine, phosgene, or other highly toxic gases.

Always use volatile and flammable solvents in an area with good ventilation or in a fume hood. Never use ether or other highly flammable solvents in a room with open flames or other ignition sources present.

Solvent Exposure Hazards

Health hazards associated with solvents include exposure by the following routes:


  • Inhalation of a solvent may cause bronchial irritation, dizziness, central nervous system depression, nausea, headache, coma, or death. Prolonged exposure to excessive concentrations of solvent vapors may cause liver or kidney damage. The consumption of alcoholic beverages can enhance these effects.
  • Skin contact with solvents may lead to defatting, drying, and skin irritation. 
  • Ingestion of a solvent may cause severe toxicological effects. Seek medical attention immediately.

The odor threshold for the following chemicals exceeds acceptable exposure limits. Therefore, if you can smell it, you may be overexposed — increase ventilation immediately.

  • Chloroform
  • Benzene
  • Carbon tetrachloride
  • Methylene chloride

Do not depend on your sense of smell alone to know when hazardous vapors are present. The odor of some chemicals is so strong that they can be detected at levels far below hazardous concentrations (e.g., xylene).

In addition, some solvents (e.g., benzene) are known or suspected carcinogens.

Reducing Solvent Exposure

To decrease the effects of solvent exposure, substitute hazardous solvents with less toxic or hazardous solvents whenever possible. For example, use hexane instead of diethyl ether, benzene or a chlorinated solvent.

The best all-around solvent is water; use it whenever possible.

The following table outlines possible solvent substitutions:

Instead of Using Substitute
Benzene Cyclohexane
Halogenated Solvents Non-Halogenated Solvents
Aromatic hydrocarbon Aliphatic hydrocarbon
Trichloroethylene 1,1,1-trichloroethane
Diethyl ether Hexane
Petroleum ether


Solvent Example: DMSO

Dimethyl sulfoxide is unique because it is a good solvent with many water-soluble as well as lipid-soluble solutes. Due to these properties, dimethyl sulfoxide is rapidly absorbed and distributed throughout the body. It can also facilitate absorption of other chemicals such as grease, oils, cosmetics, and other chemicals that may contact the skin. For these reasons wear protective clothing (gloves, lab coat, closed toed shoes) when working with this solvent.

June 2011
Revised November 2014