Tips for Lab Minimization and Substitution

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Please consider incorporating as many of the following into your research as practical.

The environment will benefit and so will your laboratory, by:

  • Lowering waste disposal costs.

  • Reducing health hazards.

  • Promoting environmental awareness.

  • Preventing pollution.

Laboratories should:

  • Substitute less hazardous chemicals for those that are hazardous.

  • Ask others on Campus if they could use your unwanted chemicals.

  • Gear the instruments and equipment in their lab to generate the least amount of waste possible.

  • Treat or destroy the hazardous by-products as the last step in experiments.

  • Purchase only the amounts necessary for use in the near future – Do not over-purchase and run the risk of having to dispose of unnecessary, unused chemicals.

Possible Substitutions:

  • For Isolation and Purification of DNA, replace chloroform-phenol extractions with kits developed by Promega (Wizard Preps – Link) or Qiagen

  • NOCHROMIX© brand laboratory glass cleaning reagent is a metal-free substitute for dichromates (CHROMERGE) in sulfuric acid. Additional information on this product can be obtained at

  • Replace benzene or carbon tetrachloride as reagents or solvents. For example, in the standard qualitative test for halide ions, cychlohexane and carbon tetrachloride are equally effective for extracting the halogen. If cyclohexane is used instead of the traditional carbon tetrachloride, the organic layer of the extract is less hazardous and more readily disposed of. The same is true of other commonly used hazardous chemicals.

  • Mercury Thermometers: Use alcohol/glycol instead of mercury thermometers. Non-mercury thermometers can be used in incubators, water baths, or other applications where mercury thermometers have traditionally been used. Please consider replacing your mercury thermomter. Mercury presents a hazard not only to faculty, staff and students in the laboratory area, but also to the local environment.

  • Bouin’s Fluid: Use a modified Davidson’s fixative in place of Bouin’s fluid (which contains picric acid) for fixing tissue. See Toxicologic Pathology 30(4):524-533 (2002) for more information

  • Xylenes

Alternatives to using Ethidium Bromide:

  • SYBR SafeTM DNA gel stain (Invitrogen):  A less toxic alternative to Ethidium Bromide.  It has been documented to be less mutagenic than ethidium bromide, but it’s acute toxicity may be higher.  Although it is less mutagenic than ethidium bromide, it still is mutagenic enough that CEHS recommends (as do other universities) that it be handled and treated like ethidium bromide. However, we still encourage you to consider this or other alternatives that might reduce the risk to your health while you are using them.  It’s major advantage is that it is as sensitive as ethidium bromide but does not require UV light for visualization.  There are many options now available that offer a safer alternative to ethidium bromide for agarose gel electrophoresis applications. Not only are these stains less hazardous to use but they are also easier and safer to dispose of. However, despite the fears of many potential users, using alternatives does not mean you have to compromise on results. In fact, many offer greater sensitivity than ethidium bromide.

  • Gel Red (Biotium): It is marketed as being the most safe, sensitive and robust nucleic acid gel stain. Less mutagenic than ethidium bromide, but more stable in storage than SYBR Safe and like ethidium bromide, Gel Red is visualized using UV light.

Ethidium bromide is an intercalating agent used in the laboratory to detect nucleic acids, particularly double-stranded DNA.  In agarose gel electrophoresis it labels DNA from PCR experiments or restriction digests with the aim of sizing nucleic acid fragments, quantifying DNA, extracting DNA of a particular size for cloning purposes or isolating full length PCR products from partial products and surplus nucleotides. Although a highly sensitive stain, ethidium bromide is notoriously unsafe. Not only is it a very strong mutagen, it may also be a carcinogen or teratogenic.