Ethidium bromide is strongly mutagenic and is irritating to the eyes, skin, mucous membranes and upper respiratory tract. The use of alternative stains is recommended whenever possible.
The following guidelines are in effect on Missouri State campuses for the disposal of solid and liquid ethidium bromide wastes, and for the decontamination of equipment contaminated with ethidium bromide. Alternative protocol may be used if approved by the Director of Environmental Management.
All solid wastes contaminated with ethidium bromide need to be disposed of through the Environmental Management Department. The wastes will be shipped off-site for incineration.
- Gel waste is to be collected in a bucket lined with two red plastic bio-hazard bags and separated from all other solid waste
- Solid waste including contaminated gloves, equipment and debris, test tubes, paper towels, etc. must be placed in a medical waste bag or red bio-hazard bag for incineration
- No liquids should be placed in the containers with the solid wastes.
Liquid ethidium bromide waste must be managed as a hazardous waste: stored in a sealed container (kept closed at all times except when adding or removing the waste) with a completed satellite accumulation waste label. When the waste container is full (or has reached the 1-year storage limit) a waste pickup should be requested by completing the electronic waste submittal form available on the Environmental Management web site.
Environmental Management personnel will determine appropriate disposal for ethidium bromide solutions, either through the University’s medical waste disposal company or by deactivation.
Decontamination of Equipment
Glass, stainless steel, and other equipment may be decontaminated with the following procedure. Proper personal protective equipment, including goggles and latex or nitrile gloves, must be worn. This procedure should be done by, or under the direct supervision of, experienced personnel.
- Wash the contaminated equipment with a paper towel soaked in the decontamination solution as described in the Lunn and Sansone Method.
The pH of the decontamination solutions is 1.8. If this is too corrosive for the surface to be decontaminated, wash with a paper towel soaked in water instead.
- Wash the surface five times with paper towels soaked in water using a fresh towel each time.
- Soak all towels 1 hour in decontamination solution.
- Neutralize the decontamination solution by adding sodium bicarbonate until the evolution of gas ceases.
- Test the decontamination solution for the presence of ethidium bromide using UV light to detect fluorescence as described in the Liquid Waste section.
- Discard the decontamination solution as a nonhazardous liquid, pouring it down the drain and flushing with copious amounts of water. The paper towels can be disposed as solid wastes by placing them in a plastic bag other than a red bag, then disposing of them into the trash. Be certain there are no free liquids in the bag. It may be necessary to add additional towels or an absorbent.
Use of bleach: The practice of oxidizing ethidium bromide with household bleach has been shown to be inefficient and may produce additional hazardous compounds, so it should be avoided.
For spills, use absorbent or a spill pillow to soak up aqueous ethidium bromide. Carefully clean up solid ethidium bromide to avoid creating dusts. Place in a sealable container and contact the Environmental Management Department for disposal.
The Environmental Management Department should also be contacted for the disposal of unused ethidium bromide (6-8334 or EnvironmentalManagement@missouristate.edu).