Standard Operating Procedure for Ethidium Bromide


Standard Operating Procedure for Ethidium Bromide

EHS SOP #: 006

Version No.: 2.0

Supercedes: N/A

Ethidium Bromide Formula



This document establishes procedures for the safe handling and disposal of Ethidium Bromide (CAS# 1239-45-8, commonly abbreviated EtBr).

Ethidium bromide is frequently used in molecular biology laboratories as a nucleic acid stain due to its ability to intercalate DNA and its fluorescent properties when exposed to ultraviolet light. While the toxicological properties have not been fully investigated, these properties also lead to suspecting ethidium bromide acts as a mutagen, carcinogen, or teratogen depending on exposure.

Health Effects

Ethidium bromide is a red-orange powder, commonly dissolved in a solution that is harmful if inhaled or swallowed. It may also cause eye, skin, and respiratory tract irritation. Seek medical treatment for all exposures.

Skin Exposure

May cause irritation. Immediately flush skin with plenty of water. Remove contaminated clothing and shoes. Wash clothing before reuse.

Eye Exposure

May cause irritation. Immediately flush eyes with plenty of water for at least 15 minutes.

Inhalation Exposure

Harmful if inhaled. May cause respiratory tract irritation. May cause methemoglobinemia characterized by dizziness, drowsiness, headaches, shortness of breath, cyanosis (bluish skin due to deficient oxygenation of blood), rapid heart rate and chocolate-brown


May cause gastrointestinal irritation with nausea, vomiting and diarrhea.

Chronic effects

May cause methemoglobinemia. May alter genetic material.

Regulatory Limits

ACGIH, NIOSH, and OSHA have no listed regulatory limits.


Based on the risk associated with the use of ethidium bromide the safety procedures outlined below are required by all research staff when working with EtBr.

Administrative Controls

  • Anyone who handles ethidium bromide is required to review this SOP and the attached Safety Data Sheet (SDS) prior to work.
  • Storage areas must be cool, dry, well-ventilated and away from incompatible substances such as strong oxidizing agents.
  • An EtBr work area should be designated and posted within the lab to limit contamination. Scan for contamination with a UV light after use to ensure the area is left clean for others.

Engineering Controls

  • Weigh and prepare stock solutions inside a chemical fume hood. If the balance is located outside of a chemical fume hood, tare a vial/flask and manipulate the powder within a chemical fume hood, seal and remove closed vessel from chemical fume hood to weigh outside.
  • Laboratory facilities storing or utilizing EtBr should have an eyewash and safety shower.

Personal Protective Equipment (PPE)

  • Nitrile gloves, a lab coat, long pants, close toe shoes, and safety glasses.

Waste Disposal

  • Ethidium bromide waste will be disposed of as a hazardous material through EHS.
  • Place solids (gels, tips, paper, plastic, etc.) in a double lined trash bag inside a cardboard box. Do not use a radioactive bag or a biohazard bag because these will be rejected at the disposal site. The waste box should be clearly labeled as “Ethidium Bromide Waste” and the box should be sealed prior to pick up.
  • Liquid waste should be collected in carboys or bottles and be clearly labeled as “Ethidium Bromide Waste.”

Accidents or Injuries

If ethidium bromide is splashed on an individual or in eyes, flush for 15 minutes with copious quantities of water and immediately contact the University Employee Occupational Health Clinic (919-966-9119).

Spill Procedures

  • Do not attempt to clean-up if you feel unsure of your ability to do so or if you perceive the risk to be greater than normal laboratory operations.
  • If a small spill occurs, wash area with soap and water, follow with 70% ethanol and check for residual EtBr with a UV light. Discard any EtBr spill-clean up materials via EHS and label as “Ethidium Bromide Solid Waste.”
  • If a large spill occurs notify others in the area and evacuate room immediately. Contact EHS (919-962-5507) during working hours and 911 if after hours.

Contact Information

Policy Contact

Environment, Health & Safety
1120 Estes Drive
Campus Box #1650
Chapel Hill, NC 27599-1650
Phone: 919-962-5507

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Article ID: 132070
Thu 4/8/21 9:23 PM
Mon 3/7/22 4:04 PM
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