Definition

• No. 1 diesel fuel is considered a light-middle grade fuel for use in abnormally low temperature conditions and with speeds and loads which vary widely.
  
  

Distillation

• No. 1 diesel has a low volatility, or vaporizing, point. In general, all diesel fuels have lower flash points than gasoline and are inherently safer. No. 1 diesel fuel distills at a lower flash point than No. 2 or No.4, providing more reliable engine performance in lower temperatures.
  
  

Emissions

• The American Society for Testing and Materials (ASTM) sets the standards for diesel fuel quality and emissions. The standard ASTM D 975 specifically states the amount of emissions an engine running on No. 1 diesel is allowed. Sulfur is the main concern in diesel emissions and the standard allows for no more than 5,000 parts per million vented to the atmosphere.