Handling Alcohols in Biodiesel Production

Methanol and Ethanol

Methanol is the driving force behind the transesterification reaction. Methanol is colorless and tasteless, with a mildly sweet odor, and is a toxic chemical. It can enter the body through inhalation, direct skin contact, or accidental swallowing. It can cause blindness or death. Because it is eliminated from the body slowly, it is considered a cumulative poison, and repeated exposure could present long-term health hazards.

Personnel working with methanol should wear protective clothing (pants, long sleeves, coveralls) and chemically resistant gloves. A breathing mask that captures organic vapors is mandatory. The cartridge in the breathing mask should be changed regularly. A full face shield is also useful.

Methanol is highly volatile, with a flash point of 12°C, and burns with a nearly invisible flame. At ambient temperature, its vapors are heavier than air and may travel some distance to a source of ignition; hence, the National Fire Prevention Association has given it a fire-hazard rating of 3 out of 4.

Methanol should be stored outside in electrically bonded and grounded steel tanks with secondary containment and under a nitrogen blanket at all times.

Methanol should not be stored or used near sources of ignition or sparks. Do not smoke near methanol. Do not use cell phones near methanol. Do not store oily rags near methanol containers. Do not store or use methanol near a refrigerator, light switch, electrical outlet, or motor.

Never grind or weld a container that contains or used to contain methanol, or that contains or used to contain the glycerol by-product of biodiesel (because this glycerol generally contains some methanol).

If a fire does occur, dry chemical powder, carbon dioxide (CO2), and alcohol-resistant foam will extinguish it by oxygen starvation. It is good practice to have two fire extinguishers at opposite ends of the workspace. Water is a second choice to extinguish a methanol fire. Water in the form of a fine mist will absorb vapors, quench heat, and provide a curtain shield for upwind advancement.

Ethanol in its absolute form (anhydrous) can also be used to make biodiesel. It is universally considered less toxic than methanol, but the same general safety guidelines for handling and storage should be observed.

First Aid for Alcohol: Call 911 and get help immediately.

Inhalation: Move victim to fresh air and keep warm and rested. Monitor breathing; if breathing is difficult, do not give mouth-to-mouth resuscitation as this may expose rescuer to methanol. Instead, use oxygen if trained to do so.

Ingestion: Give two glasses of water and induce vomiting, if directed to do so.

Eyes: Flush with water for at least 15 minutes.

Skin: Wash with soap and water for at least 15 minutes. Remove clothing and shoes. Patient should be seen at a health-care facility.

Additional Topics on Biodiesel Safety

Safe Chemical Handling in Biodiesel Production

Safety in Small-Scale Biodiesel Production

Safety in Large Biodiesel Production

Handling Strong Acids in Biodiesel Production

Handling Strong Bases in Biodiesel Production

Laboratory Safety in Biodiesel Production


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Contributors to This Article


  • Tom Karsky, Extension Professor and Extension Safety Specialist, University of Idaho

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