Ethidium Bromide (EtBr) Disposal
Ethidium bromide (EtBr) is a strong mutagen and a possible carcinogen or teratogen.
When you work with EtBr, you must wear a lab coat, chemical splash goggles, and nitrile gloves.
Always use caution when using an ultraviolet light while working with EtBr.
Always use a chemical fume hood during processes that can generate EtBr dusts or mists.
Ethidium Bromide, unused
- Collect for disposal by Health & Safety
Aqueous solutions containing < 5 mg/L EtBr
- Dispose to the sanitary sewer.
Aqueous solutions containing > 5 mg/L EtBr
If the solutions contain no other Hazardous Materials (organics, salts, metals, etc.)
- For every 100 ml of EtBr solution add
- 20 ml 5% hypophosphorous acid solution and
- 12 ml 0.5 M sodium nitrite solution.
- Stir mixture and let sit for 20 hours
- Neutralize with sodium bicarbonate, then dispose into the sanitary sewer (sink).
Solvents containing EtBr
- Collect for disposal by Health & Safety.
Radioactive EtBr solutions
- Collect for disposal by Health & Safety, Radiation Safety
Gels containing EtBr
- Break up Gels
- Chemically degrade as noted above
- Dispose to the sanitary sewer, or,
- Dry Gels and Collect for disposal by Health & Safety
Materials (gloves, pipettes, tips, etc.) used with EtBr
- Place in secure container (taped box with plastic bag liner) and place the container directly into a dumpster.
Commercially available products, like the “Destaining Bags” produced by AMRESCO provide an alternative method of treatment for solutions.
- The destaining bags are simple and inexpensive.
- Drop a destaining bag into your solution,
- Periodically swirl it around a few times,
- Let it stand overnight.
- In the morning, remove the bag and collect for disposal by Health and Safety.
- Perform UV check of the solution. If it no longer fluoresces, pour the solution down the drain- provided no other hazardous chemicals are present.
Whenever possible, use a less hazardous chemical for the identification of DNA.
Sigma-Aldrich produces a product called REDTAQ DNA Polymerase. It is an inert red tracer conjugated to a polymerase.
Other EtBr disposal procedures should be avoided.
The practice of oxidizing ethidium bromide with household bleach is inefficient and may produce additional hazardous compounds.