Working Safely with Ethidium Bromide
DESCRIPTION
Ethidium bromide, (Dromilac, homidium bromide), CAS # 1239-45-8, is commonly used in molecular biology laboratories for visualizing nucleic acids using electrophoresis and other gel-based nucleic acid separation methods. Ethidium bromide fluoresces when exposed to ultraviolet light and exhibits a vivid red-orange color when bound to nucleic acids.
HAZARDS
Ethidium bromide is a potent mutagen and is an irritant to the eyes, skin and respiratory tract. Ethidium bromide can be absorbed through exposed skin and mucus membranes.
Personal Protective Equipment
Protective Clothing: Wear standard laboratory apparel including a fully-buttoned lab coat, long pants and closed-toe shoes.
Eye Protection: Wear safety glasses with side shields at all times within the laboratory. Wear chemical splash goggles when there is a splash hazard.
Gloves: Wear disposable nitrile gloves to protect exposed skin on the hands. Wash hands thoroughly after removing gloves.
Special Work Practices
Locations where ethidium bromide is used or stored must be identified as "Designated Areas" and demarcated with either printed Designated Area tape available from EHRS or yellow tape with "DESIGNATED AREA" written upon it.
Procedures requiring the use of ethidium bromide powder or having the potential to generate aerosols must be performed in a fume hood. To minimize inhalation exposure, purchase ready-made stock solutions or tablets in lieu of preparing stock solutions from ethidium bromide powder.
During normal use, small spills may occur and residues may build up on equipment and other laboratory surfaces. A solution of soap and water is recommended for cleaning small spills and removing residues on equipment and laboratory surfaces.
Due to the potential for equipment contamination, ethidium bromide-containing agarose gel should not be heated in a microwave.
Since ethidium bromide is used in conjunction with an ultraviolet light source, please review the Ultraviolet Radiation Safety Fact Sheet.
Emergency Procedures
Eye Contact: Immediately irrigate. Hold eyes open and irrigate for 15 minutes. Obtain medical attention.
Skin Contact: Remove contaminated clothing. Immediately wash affected areas with soap and water. Obtain medical attention.
Ingestion: Obtain medical attention immediately.
Inhalation: Seek medical attention if symptoms develop (wheezing, coughing, shortness of breath, burning in mouth, throat or chest).
Medical Attention: Between the hours of 8:00 AM and 3:30 PM, staff should visit Occupational Medicine located on the first floor of Silverstein Pavilion at the University of Pennsylvania Medical Center. During evenings and weekends, staff should visit the emergency room at the University of Pennsylvania Medical Center located on the ground floor of Silverstein Pavilion. Students experiencing minor symptoms should visit Student Health located in Penn Tower while those with more severe symptoms should visit the emergency room.
Ethidium Bromide Waste Disposal
Ethidium Bromide waste in concentrated or solid form is collected as hazardous waste and should not be flushed down the drain or disposed of in the trash. Please review the Ethidium Bromide Policy for additional information. Waste should properly labeled and handled as follows:
Write the date received and the date opened on all containers of ether. Discard open containers of ether within six months of opening.
Liquids: Small quantities of aqueous solutions containing an ethidium bromide concentration of less than 10 µg/ml (10 ppm) may be flushed down the drain. Non-aqueous solutions and solutions containing an ethidium bromide concentration of greater than 10 µg/ml will be picked up by EHRS. EHRS provides 19-liter polyethylene carboys for large volume liquid waste collection. Laboratories are responsible for providing small volume waste containers.
Contaminated sharps (needles, syringes, slides, broken glass, etc.): Discard in an infectious waste sharps container clearly labeled "CHEMICAL CONTAMINATED SHARPS-DO NOT AUTOCLAVE". Discard the sharps container as infectious waste without autoclaving when it is 2/3 to 3/4 full.
Solids (contaminated gloves, centrifuge tubes, towels, etc.): Store in an aproperly labeled translucent polyethylene container for disposal as chemical waste. Do not use glass containers.
Gels: Low concentration gels (< 10 µg/ml) may be wrapped in plastic wrap and discarded in the trash. Higher concentration gels should be disposed of as contaminated solids described above.
Spill Procedures
Small spills of ethidium bromide solutions should be cleaned by laboratory staff. For large spills outside the fume hood, evacuate/restrict access to the laboratory and contact EHRS for assistance.
Individuals cleaning spills must wear appropriate protective equipment as described in the Personal Protective Equipment section of this document.
Spills of ethidium bromide solutions should be cleaned using absorbent pads followed by surface decontamination using soap and water. Spilled dry material should first be covered with moist absorbent pads to avoid generation of dust.
Ensure all materials contaminated as a result of the cleanup process are collected and disposed of as hazardous waste as described in the Ethidium Bromide Waste Disposal section of this document.
Additional EHRS Services
Health Hazard evaluations: EHRS is available to review laboratory work practices/procedures and make recommendations to promote the safe use of ethidium bromide in the laboratory.
Training: EHRS conducts initial laboratory safety training sessions and provides on-line annual refresher training for all laboratory staff. Initial training session dates are published in the University of Pennsylvania Almanac and on our web site.
Hazardous waste collection: Request collection by calling (215) 898-4453 or online.
Please contact EHRS at (215)898-4453 to arrange for any of the above services.