Summary 

MS-222 is used for anesthesia or euthanasia of fish, amphibians and other aquatic, cold-blooded animals. It is typically purchased as a powder and dissolved in water prior to use. Overexposure to MS-222 in humans may cause skin, eye and respiratory irritation. There is one report in the literature of reversible retinal toxicity in a scientist with long-term exposure to MS-222 powder. 

Preparation of MS-222 Working Solutions 

1. Wear a lab coat, nitrile exam gloves and safety glasses when handling powder. 
2. Preparation in a fume hood may result in dispersal of the product due to air disturbances. Weigh the solid in an area free from drafts. Place wet paper towels around the balance to catch dropped powder. 

Working with Aquatic Animals Exposed to MS-222 Solutions 

1. Wear disposable gloves when handling animals that have been exposed to MS-222 or when placing hands into tanks containing MS-222. If the animal has been thoroughly rinsed with clean water after exposure to MS-222, gloves are not necessary. 

Spills 

Powder 

1. Wearing lab coat, nitrile gloves and eye protection, cover powder with paper towels, spray lightly with water and scoop material and paper towels into a container for disposal as hazardous chemical waste by EHS. 

Liquid 

1. For small spills of liquid, clean with a paper towel and dispose into regular trash. 
2. For larger spills (500 mls or greater), obtain absorbent material from an EHS spill kit. Place used absorbent material into a plastic bag and contact EHS for assistance with disposal and replacement of spill absorbent material. 

Disposal 

1. Unused or expired powder and stock solutions must be disposed of as hazardous chemical waste through EHS. 
2. Working solutions for anesthesia and euthanasia may be disposed of into the sanitary sewer. 
3. If working with MS-222 in the field, working solutions should be diluted and disposed of in soil, away from storm drains, creeks, lakes or other bodies of water. 

For additional information, contact: Environmental Health and Safety, 8-5294 

References: Conroy CJ, Papenfuss T, Parker J, Hahn NE. 2009. Use of Tricaine Methanesulfonate (MS222) for Euthanasia of Reptiles. Journal of the American Association for Laboratory Animal Science. Jan 48(1):28-32. 

Follow these precautions when conducting rodent perfusions with formalin solution. 

Put on personal protective equipment 

• Wear gloves, preferably nitrile, disposable gown, head covering, surgical mask and safety glasses.

Set-up work area 

• Turn on hose at downdraft table. 
• Direct water flow away from the downdraft table ventilation intake to prevent water infiltration into the ventilation ductwork. 
• If giving multiple injections of an anesthetizing agent, don’t re-cap needles. 
• Place uncapped needles in a rigid tray between uses. 

Clean up the area

• Formalin solution/blood waste created during a rodent perfusion should be collected and disposed of through the EHS Chemical Waste Program. 
• Wash downdraft table, including underside of perforated table surface. 
• Disinfect with Virkon® or other LAR-approved disinfectant. 
• After removing PPE, place soiled PPE in regulated medical waste container and wash hands.

Exposures to formalin solution / rodent body fluids

• Eyes: rinse at eyewash for 15 minutes 
• Percutaneous injuries: rinse with warm water/soap. 
• Report all exposures, regardless of severity, to Employee Health (258-5035) and your supervisor.

EHS Contact: Meagan Fitzpatrick, Biosafety Officer, 609-258-6258

Chemicals that are highly toxic or corrosive, known or suspected carcinogens, reproductive hazards, teratogens, antineoplastic agents and mutagens may be used in animal protocols. It is the responsibility of the Principal Investigator to evaluate potential exposure risks of hazardous chemicals and drugs to lab and animal husbandry staff during:

• chemical preparation 
• animal dosing 
• husbandry activities, including cage changing and disposal of bedding 

Information on hazardous chemicals and drugs can be found at: 

Princeton University Environmental Health and Safety MSDS page: 

NIOSH List of Antineoplastic Drugs 

National Toxicology Program 

Toxicology Data Network 

Assessing Hazards 

Exposure risk to hazardous chemicals and drugs is a function of: 

• toxicity, half-life and metabolic byproducts of the compound 
• method of preparation 
• concentration and method of administration 
• amount of material present in animal excreta and bedding 
• engineering controls, work practices and personal protective equipment 

Principal Investigator 

1. Conduct a risk assessment to determine engineering controls, safe work practices, and personal protective equipment that are needed when working with the hazardous chemical. Communicate this information to laboratory and LAR staff expected to work with these materials. See Table 1.
2. Determine if the hazardous chemical or drug is excreted. 
3. Contact EHS to determine if animal bedding waste must be treated as hazardous chemical waste.
4. Advise laboratory staff to post hazardous chemical labels on cages and place hazard warning signs on housing room doors (See Figure 1) after animal(s) has been exposed. 
5. Communicate to LAR animal husbandry staff if the hazardous chemical or drug will be excreted in animal waste. 
6. Provide Material Safety Data Sheets to LAR Associate Director.

LAR Associate Director 

1. Review safe work practices, found in Table 1, with LAR husbandry staff. 
2. Ensure that all equipment required to control exposure is available for use within the laboratory animal facility. 

Environmental Health and Safety 

1. Review Applications for Animal Use that involve the administration of hazardous chemicals to animals. 
2. Provide guidance to PI, laboratory and LAR staff on appropriate engineering, PPE and work practice controls and waste disposal procedures required to prevent exposures and comply with applicable regulations. 
3. Consult with University Health Services to determine if medical surveillance is required for personnel involved in research

Table 1: Controlling Exposure to Hazardous Chemicals Used in Animal Protocols

Reviewed by EHS: February 2015
Contact: Meagan Fitzpatrick, Biosafety Officer, 609-258-6258