What is MS-222?
Tricaine methane sulfonate, more commonly known as MS-222, is frequently used as an anesthetic for fish and amphibians. It is water-soluble and acts by depressing the central nervous system. It is approved by the American Veterinary Medical Association (AVMA) as an acceptable method of euthanasia for the aforementioned species, if it is complemented with a secondary method to ensure death.
MS-222 comes in a powdered form and should be stored in a cool dry place and protected from light. The primary hazard of MS-222 is that it is a respiratory, eye and skin irritant. This chemical is an environmental hazard and should be disposed of as regulated chemical waste.
The use of MS-222 must be approved in the IACUC protocol as an anesthetic or euthanasia agent used in animals. Pharmaceutical grade MS-222 (Syncaine [formally Tricaine-S]) must be used for animal experiments unless justification is provided and approved in the IACUC protocol for use of a non-pharmaceutical grade product.
PPE Requirements
Minimum Personal Protective Equipment (PPE) that must be worn when handing MS-222 include:
- Laboratory coat with cuffed sleeves.
- Safety glasses, goggles or face shield over eye protection
- Gloves long enough so that there is no skin exposed between the glove and the lab coat sleeve.
Safe Handling
Always handle MS-222 powder in a well-ventilated area, a class II biosafety cabinet, or a certified fume hood. An N95 respirator may be required when working with powdered chemical. Consult the University’s Respiration Protection Program, if necessary. Protect your skin and eyes by wearing PPE.
MS-222 solutions should be prepared in water that is similar to the water conditions of the animal. The water should have adequate levels of dissolved oxygen, and appropriate pH, temperature, alkalinity, hardness and salinity for the subjects. MS-222 may acidify aqueous solutions; therefore, a buffered solution (i.e. sodium bicarbonate) should be added to maintain an optimal pH (7.0-7.4) for the species. A concentration between 100 to 400 mg/liter is typical, but researchers can refer to the manufacturer’s dosing chart when needed. It is recommended that the dosing be tested prior to experimentation considering that variables such as temperature, water hardness, and size of the animal, may impact the efficiency of this chemical.
For best results, use fresh MS-222 solutions. If storage is required, stocks must be refrigerated, stored in a tinted or opaque container, labeled with the name of the drug, hazard warning, concentration, date of preparation and expiration date (30 days from preparation).
In the field, don PPE and work in a well-ventilated area. Avoid working with the powdered chemical in a location that could cause the powder to blow into a breathing zone or onto unprotected skin.
After work cleaning procedure:
- Decontaminate work surfaces with a mild detergent and water or 70% ethanol.
- Dispose of paper towels and cleaning materials as chemical-contaminated waste.
- Remove gloves and PPE properly to avoid contamination.
- Wash hands thoroughly with soap and water.
Laboratory Waste and Carcass Disposal
- Liquid waste: Collect concentrated stock solutions of MS-222 or dilute solutions from small exposure tanks (≤20 L) in a designated, labeled chemical waste container for disposal through the University’s hazardous waste program. Contact HSRM (612) 626-1604 or [email protected] for additional disposal options for large volumes or waste generated off campus. Disposal options will be evaluated on a case-by-case basis.
- Solid waste: (e.g. solid chemical, contaminated gloves, paper towels): Place in a hazardous chemical waste container.
- Carcasses: Animals euthanized with MS-222 should be treated as biological waste. Use a red bag and freeze until disposal through the red bag waste stream.
Spill Procedures
First, stop work and assess the size/type of spill. For major spill, isolate the area and contact HSRM. Don appropriate PPE to contain and clean up the spill. For powder spills: Lightly mist the area with water to prevent dust becoming airborne. DO NOT sweep or vacuum the waste. Use a damp disposable towel to collect the powder. Avoid creating dust by working slowly. For liquid spills: surround the area with absorbent pads or towels to prevent spread. Absorb the rest of the spill avoiding unnecessary splashes.
After cleanup, collect the contaminated material in a solid waste container and clean the affected surface with a mild detergent of 70% ethanol. Ensure no residue remains. Label the cleanup material waste with at least group name, chemical name, location of the spill and date. Notify the University Hazardous Waste program for pick up.
Emergency Procedures
In case of exposure to eyes or skin, flush the area for 15 minutes with running water. Seek medical treatment as soon as possible. University employees may choose to go to the nearest Emergency Department or a medical provider of their own choice. It is encouraged to visit the Occupational Health Providers listed on the Occupational Health website.
Fill out a First Report of Injury promptly whenever a work injury occurs, regardless of severity. When you arrive at the clinic, mention that your visit is in connection with a work-related incident and give them your First Report of Injury Claim number and chemical SDS if you have it. Outside of normal business hours, please visit the nearest Emergency Department.