Safety, Health, and Environmental Issues

Neat biodiesel contains no hazardous materials and is generally regarded as safe. A number of studies have found that biodiesel biodegrades much more rapidly than conventional diesel. Users in environmentally sensitive areas such as wetlands, marine environments, and national parks have taken advantage of this property by replacing toxic petroleum diesel with biodiesel.

Like any fuel, biodiesel will burn; thus, certain fire safety precautions must be taken as described in this section. Of much greater concern are biodiesel blends that may contain kerosene or petroleum diesel. Kerosene is highly flammable with a flash point of 38°C to 72°C (100°F to 162°F). Diesel fuel is generally considered flammable—its flash point is 52°C to 96°C (126°F to 204°F). The flash point of biodiesel is required to be greater than 93°C (200°F), so is considerably less dangerous. However, biodiesel blends will have flash points in between diesel and biodiesel. The U.S. Department of Transportation considers a blend flammable and the Resource Conservation & Recovery Act of 1976 considers it to be ignitable if the flash point is lower than 60°C (140°F) or combustible if the flash point is 60°C to 93°C (140° to 200°F).