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Chemical Waste Disposal


Pollution Prevention Ideas for Laboratories

There are numerous ways that laboratory workers can reduce the impact that our laboratories have on the environment. All laboratory workers are asked to consider pollution prevention opportunities for all of their operations. This includes reducing or eliminating chemical use and chemical waste production; substituting less hazardous materials; conservation of water or electricity; and any other means of reducing environmental impact.

The following are a number of initiatives that have resulted in waste minimization and/or pollution prevention in Princeton University laboratories. If you have any other ideas or successes, please contact Steve Elwood at 258-6271.


  • Avoid using fresh solvents for cleaning glassware. Filter and reuse solvents for this purpose or use Alconox and elbow grease initially.
  • If solvents are needed for cleaning, minimize the amount by not simply using the force of flow from a squeeze bottles.
  • Do not use chromium-based glass cleaners (e.g., Chromerge®). No-Chromix®, Micro 90®, enzymatic cleaners, detergents, etc. can be just as effective.
  • For sterilizing equipment, use quaternary amine detergents instead of isopropyl alcohol.
  • Use ethanol instead of methanol in dehydrating and rinsing processes.
  • Use ultrasonicators and/or industrial dishwashers instead of solvents for cleaning.
  • Purchase better brushes to reduce the temptation of opting for a solvent for cleaning.
  • Keep extra glassware on hand and/or use drying oven to reduce the need for rinsing with solvent to hasten drying of glassware.

Mercury Alternatives

  • Use non-mercury thermometers. EHS will replace most thermometers with compatible digital or alcohol/glycol thermometers upon request FREE OF CHARGE.
  • For differential manometers, use water or calibrated oils instead of mercury or switch to pressure transducers or electronic pressure gauges.
  • Notify EHS as soon as mercury-filled equipments are taken out of service to ensure timely disposal.

Equipment Modifications

  • Upgrade instrumentation or move to automation to conserve energy and chemical resources.
  • Use capillary columns instead of micropore or large-diameter columns in gas chromatographs or HPLC equipment.
  • Use diaphragm pumps instead of those requiring water circulation to conserve water.
  • Replace traditional thermal distillation apparatus with newer “push”, dry solvent purification systems for purifying and drying solvents. Eliminates the need for a fume hood and conserves energy, water and solvents. Minimizes waste production and significantly reduces fire risk.


  • Neutralize acids and bases and pour non-toxic, pH 4-9 material down the drain. See Elementary Neutralization for further instruction.
  • Add a treatment or deactivation step to experimental procedures to reduce or eliminate hazardous waste production. Consult EHS for advice.
  • Clean up and neutralize spills such that all or most of the waste can be disposed via the drain or regular trash. See instructions for
  • Use charcoal filtration, such as funnel kits or Green Bags®, to remove ethidium bromide from solutions. This minimizes the amount of waste and eliminates disposal of bleach solutions down the drain or the use of other potentially hazardous chemicals for deactivating the ethidium bromide.


  • Replace benzene or carbon tetrachloride as reagents or solvents. For example, in the standard qualitative test for halide ions, cyclohexane 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 is more readily disposed. The same is true of other commonly used hazardous materials.
  • Simplify procedures to potentially eliminate a step that utilizes chemicals.
  • Use microscale techniques.
  • For isolation and purification of DNA, replace chloroform-phenol extractions with new techniques developed by Promega (Wizard Preps 800-356-9526) or Stratagene (Lambda DNA Purification Kit 800-424-5444).
  • Use chilled water loops instead of continuously running water for cooling.
  • For fly morgues, use propylene glycol in place of ethanol. The spent material can be disposed via the drain.
  • 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 and reference (available through University Library Services).


  • Review chemical inventory annually. Such review can help avoid purchase of materials already on hand (but forgotten) and can help ensure prompt disposal of unneeded materials.
  • Purchase smaller quantities to reduce leftover, unusable chemicals. The American Chemical Society estimates that 40% of waste generated in research labs consists of unused chemicals.
  • Review laboratory procedures annually. Look for ways to reduce or eliminate the use of hazardous chemicals.
  • Centralize chemical purchasing in your lab. Assigning one person to purchase chemicals can help reduce the likelihood that duplicate orders will be made.
  • Share unused, unopen containers or unused portions of materials with other labs.


  • Teaching labs are a great place for waste minimization. See Minimizing Waste in Teaching Labs for more information.
  • Seal containers of volatile materials well. Be sure that pumps fit the container opening to prevent loss of material from evaporation.
  • Turn off equipment that is not in use. For example, turn off the rotary arm of a rotovap when not in use.
  • Be prepared for spills. Cleaning up spills can generate a lot of waste. Minimize the likelihood of spills by using secondary containers. Have the right kind of spill control materials to minimize the amount of debris. Consider whether gloves or other protective equipment is truly contaminated enough to warrant disposal as hazardous waste.

Have an Idea?
Tell EHS about your ideas and your successes in reducing the amount of hazardous waste generated and/or conservation of energy, water or other resources. Contact Steve Elwood at 258-6271.


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