Any liquid having a flash point of not more than 60°C (140°F) with the following exceptions: liquids meeting any of the Class 2 definitions; or mixtures having one or more components with a flash point greater than 60°C (140°F) that make up at least 99% of the total volume of the mixture.

Note: Labels used to identify a subsidiary risk must have the class number obliterated.

Also see:

What are the Federal Regulations for Hazardous Materials Labeling?