Handling Strong Acids in Biodiesel Production

Sulfuric and Hydrochloric Acids

Acids may be used in treating high free fatty acid (FFA) feedstocks, neutralizing base catalyst and splitting soaps in the washing process, and/or in treating the crude glycerin by-product. Acids are colorless and can be extremely damaging to all body tissue. Acids cause rapid tissue destruction and serious chemical burns. Their vapors can cause eye, nose, and throat irritation; shortness of breath; pulmonary edema; or other serious ailments. Workers should wear acid-resistant protective clothing and gloves, a face shield, and a respirator where exposure to mist or fume is possible.

Acids can decompose at high temperatures, forming toxic gases. Acids are nonflammable but react violently with water, generating large amounts of heat, and may spatter.

Heat is produced when acids and water are mixed. If diluting acids with water, always add the acid to water in order to minimize excessive temperature rise. Never add water to the acid.

Acids can react with combustible materials, generating heat. Ignition can occur if sufficient heat is generated. Acids also react with most metals (particularly when diluted with water) to form flammable hydrogen gas which may create an explosion or fire hazard. If fire does occur, use carbon dioxide or dry chemical extinguishers. Use water spray only if absolutely necessary to cool fire-exposed containers.

Store acids in a dry, cool, well-ventilated area away from alkali or fuels. Keep in tightly closed glass or plastic containers which are appropriately labeled. If spilled, acids can be neutralized with alkali such as sodium carbonate or sodium bicarbonate, soda ash, lime, or limestone granules. The neutralization will liberate gaseous carbon dioxide.

Symptoms of overexposure include tissue damage, respiratory tract damage, severe eye damage, and blindness.

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

Eyes: Immediately flush with water for at least 15 minutes. Flush under eyelids by lifting them. See doctor as soon as possible.

Skin: Flush with water. Remove clothing and continue flushing.

Inhalation: Remove to fresh air and restore breathing. Get medical help.

Ingestion: Do not induce vomiting unless directed by 911 operators. Dilute stomach contents by giving water or milk together with milk of magnesia if not unconscious.

The process of producing biodiesel should be made as safe as possible by developing and adhering to a safety protocol plan for each facility. Accidents can be avoided with thorough training of personnel and strict adherence to all local, regional, and national safety regulations. If an accident does occur, proper remediation protocol should be in place to effectively deal with any situation to minimize the extent of the loss. An emergency plan can avoid confusion should accidents occur.

Additional Topics on Biodiesel Safety

Safe Chemical Handling in Biodiesel Production

Safety in Small Biodiesel Production

Safety in Large Biodiesel Production

Handling Alcohols in Biodiesel Production

Handling Strong Bases in Biodiesel Production

Laboratory Safety in Biodiesel Production


For Additional Information

  • Biodiesel Safety video. 10-minute video, created by the University of Idaho, helps home biodiesel producers understand how to safely handle the chemicals used in biodiesel production.



Contributors to This Article


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

Peer Reviewers

  • Don Wysocki, Extension Soil Scientist, Oregon State University