Flame Sterilization¶

Flame sterilization uses alcohol and an open flame to sterilize tools such as spreaders and inoculating loops. Because it combines a flammable solvent with an ignition source, it creates a fire and burn hazard.

Before doing this procedure, you must:

read this page
read and sign the required SOPs listed under Required SOPs
pass the quiz
receive in-person training from your supervisor or designee

This page does not replace hands-on training.

Required SOPs¶

Read and sign both of the following SOPs before doing flame sterilization:

Local rules for this lab¶

Flame sterilization may only be done in the chemical hood.
Flame sterilization may only be done by supervisors who have completed this training.
Use the blue fire-resistant lab coats associated with this lab in B144.
Do not use the lab coats in the tissue culture room B146 for this procedure.
Return lab coats to their correct room after use.
The eyewash, safety shower, spill kit, and fire extinguisher for this procedure are in the safety corner of B144, in the northeast corner by the door.
When performing this procedure, inform your lab colleagues.

Main hazards¶

The main hazard is using a flammable solvent next to an open flame. Fire can start if too much solvent is used, the container tips, droplets spread onto the bench, or combustible materials are nearby.

Burns are also possible. Gloves, sleeves, hair, and clothing can catch fire.

Safe setup and technique¶

Use the smallest practical amount of solvent. Do not exceed 100 mL.
Keep at least 12 inches between the flame and the solvent container.
Clear the area of paper, wipes, notebooks, and other combustible or hazardous materials. There should be nothing combustible within two feet of the work area.
Do not work under shelves, cabinets, or overhanging equipment.
Use a stable glass or metal solvent container with straight walls. It should be restrained, placed in a non-flammable secondary container, or be wider than it is tall.
Do not leave the tool sitting in the solvent.
After dipping the tool, gently tap it on the container and remove excess alcohol before flaming it. Droplets on the bench can spread and volatilize, causing fire to spread rapidly.
Work standing up so you can move away quickly if there is a flare or spill.
Inspect the flame source and associated tubing or hoses before use.

The order matters:

Dip the tool in solvent.
Remove excess solvent.
Pass the tool briefly through the flame.

Never flame the tool first and then dip it into solvent.

This training applies to flame sterilization as performed in B144. Do not treat this page as general training for other sterilization methods or other lab spaces.

PPE¶

Safety glasses with side shields or chemical splash goggles
Nitrile gloves that fit properly and are dry before you begin. Note: nitrile gloves are combustible — if ignited, they can severely burn your skin. This is why dry gloves and correct technique matter.
Do not wear latex gloves
Polyester-cotton or 100% cotton lab coat
Long pants
Closed-toe, closed-heel shoes
Legs and ankles covered
Non-synthetic clothing
Keep medium and long hair tied back

Emergency response¶

If clothing catches fire, do not run. Stop, drop, and roll, or use the safety shower immediately to extinguish the fire.

After the flames are out, flush any burn with low-pressure running water. Do not apply ice. Do not rub the area. If a finger is burned, do not put it in your mouth.

Seek medical attention for any burn.

If there is an eye exposure, use the eyewash immediately and rinse for at least 15 minutes.

If the situation is life-threatening, someone is unconscious or not breathing, or you cannot control the hazard safely, call 911.

Before doing flame sterilization, you must read this page, read and sign both SOPs listed under Required SOPs, pass the quiz, receive in-person training, and sign the paper SOPs on the safety board.

Flame Sterilization Quiz¶

Answer all questions correctly to pass. If you miss any, the quiz resets with a new randomized set.