Erlenmeyer FlaskChemical Safety

Pollution Prevention in Laboratories: The "How To" Guide

What is a hazardous waste?

Knowing what chemicals are regulated as hazardous wastes provides a starting point for waste minimization. Wastes are classified as hazardous if they meet at least one of the following characteristics:

How to start - setting up a new laboratory

A number of chemicals are also listed as hazardous if they become wastes. There are the P-list of acutely toxic materials and the U-list of toxic materials. Metals of concern for the toxic characteristic are arsenic, barium, cadmium, chromium, lead, mercury, selenium and silver.

How to start - Improving an existing laboratory

The following is a brief description of chemicals to avoid when planning laboratory experiments for research, analytical or instructional purposes.

Recommendations (in order of priority):

A. Eliminate or reduce the use of reactive chemicals, where possible, for both safety and hazardous waste reasons. If wastes from laboratory work are reactive, deactivate their reactive characteristic as part of the experiment.

B. Eliminate or reduce the use of halogenated solvents, where possible. Many halogenated solvents are carcinogens or suspected carcinogens. If such solvents must be used, investigate redistillation to minimize disposal requirements.

C. Reduce or eliminate the use of arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver where possible. If silver must be used, recover for reclamation.

D. Eliminate or reduce the use of oxidizers, where possible.

E. Eliminate or reduce the use of non-halogenated flammable solvents, where possible. Try to find nonflammable, biodegradable substitutes. If such solvents must be used, investigate redistillation to minimize disposal requirements.

F. Eliminate or reduce the use of highly toxic chemicals, where possible.

G. Neutralize all corrosive solutions as part of the experiment. Waste acid or base may be neutralized to a pH between 6 and 12 and then disposed of down the drain, provided that the solutions do not contain any toxic materials that would classify them as hazardous wastes.

Use the following substitutions where possible:

Original Material




Stearic acid

In phase change and freezing point depression

Chromic acid cleaning solutions


Last resorts: KOH/Ethanol bath, acid bath, or NoChromix

Ethyl Ether

Methyl t-butyl ether

Avoid forming explosive peroxides



For storage of biological specimens

Mercury Thermometers

Red liquid thermometers



Limonene based extract

 For histology uses


Replace hazardous or toxic materials with nonhazardous or less hazardous products.


Ways to reduce quantities of hazardous or toxic chemicals:


Reusing material (after processing, if needed) in original process or reclamation for use in other processes


Incorporate these steps into experimental procedure.


Contact the Division of Research Safety, Chemical Safety Section (333-2755 or via e-mail) or visit our web site:

Other Chemical Safety Fact Sheets are available from the Chemical Safety Section at our web site:

References for Treatment Procedures

Armour , M. A . , Hazardous Laboratory Chemicals Disposal Guide, CRC Press, Boco Raton, 1991, 464 pages.

Lunn , George, and Sansone , Eric, Destruction of Hazardous Chemicals in the Laboratory, Wiley- Interscience NY , NY 1990, 271 pages.

National Research Council, Prudent Practices for Disposal of Chemicals from Laboratories, National Academy Press, 2101 Constitution Ave., Washington, DC 20418, 1983, 282 pages.

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